fs/ext4/dir.c

   1 /*
   2  *  linux/fs/ext4/dir.c
   3  *
   4  * Copyright (C) 1992, 1993, 1994, 1995
   5  * Remy Card (card@masi.ibp.fr)
   6  * Laboratoire MASI - Institut Blaise Pascal
   7  * Universite Pierre et Marie Curie (Paris VI)
   8  *
   9  *  from
  10  *
  11  *  linux/fs/minix/dir.c
  12  *
  13  *  Copyright (C) 1991, 1992  Linus Torvalds
  14  *
  15  *  ext4 directory handling functions
  16  *
  17  *  Big-endian to little-endian byte-swapping/bitmaps by
  18  *        David S. Miller (davem@caip.rutgers.edu), 1995
  19  *
  20  * Hash Tree Directory indexing (c) 2001  Daniel Phillips
  21  *
  22  */
  23
  24 #include <linux/fs.h>
  25 #include <linux/buffer_head.h>
  26 #include <linux/slab.h>
  27 #include "ext4.h"
  28 #include "xattr.h"
  29
  30 static int ext4_dx_readdir(struct file *, struct dir_context *);
  31
  32 /**
  33  * Check if the given dir-inode refers to an htree-indexed directory
  34  * (or a directory which could potentially get converted to use htree
  35  * indexing).
  36  *
  37  * Return 1 if it is a dx dir, 0 if not
  38  */
  39 static int is_dx_dir(struct inode *inode)
  40 {
  41         struct super_block *sb = inode->i_sb;
  42
  43         if (ext4_has_feature_dir_index(inode->i_sb) &&
  44             ((ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) ||
  45              ((inode->i_size >> sb->s_blocksize_bits) == 1) ||
  46              ext4_has_inline_data(inode)))
  47                 return 1;
  48
  49         return 0;
  50 }
  51
  52 /*
  53  * Return 0 if the directory entry is OK, and 1 if there is a problem
  54  *
  55  * Note: this is the opposite of what ext2 and ext3 historically returned...
  56  *
  57  * bh passed here can be an inode block or a dir data block, depending
  58  * on the inode inline data flag.
  59  */
  60 int __ext4_check_dir_entry(const char *function, unsigned int line,
  61                            struct inode *dir, struct file *filp,
  62                            struct ext4_dir_entry_2 *de,
  63                            struct buffer_head *bh, char *buf, int size,
  64                            unsigned int offset)
  65 {
  66         const char *error_msg = NULL;
  67         const int rlen = ext4_rec_len_from_disk(de->rec_len,
  68                                                 dir->i_sb->s_blocksize);
  69
  70         if (unlikely(rlen < EXT4_DIR_REC_LEN(1)))
  71                 error_msg = "rec_len is smaller than minimal";
  72         else if (unlikely(rlen % 4 != 0))
  73                 error_msg = "rec_len % 4 != 0";
  74         else if (unlikely(rlen < EXT4_DIR_REC_LEN(de->name_len)))
  75                 error_msg = "rec_len is too small for name_len";
  76         else if (unlikely(((char *) de - buf) + rlen > size))
  77                 error_msg = "directory entry across range";
  78         else if (unlikely(le32_to_cpu(de->inode) >
  79                         le32_to_cpu(EXT4_SB(dir->i_sb)->s_es->s_inodes_count)))
  80                 error_msg = "inode out of bounds";
  81         else
  82                 return 0;
  83
  84         if (filp)
  85                 ext4_error_file(filp, function, line, bh->b_blocknr,
  86                                 "bad entry in directory: %s - offset=%u(%u), "
  87                                 "inode=%u, rec_len=%d, name_len=%d",
  88                                 error_msg, (unsigned) (offset % size),
  89                                 offset, le32_to_cpu(de->inode),
  90                                 rlen, de->name_len);
  91         else
  92                 ext4_error_inode(dir, function, line, bh->b_blocknr,
  93                                 "bad entry in directory: %s - offset=%u(%u), "
  94                                 "inode=%u, rec_len=%d, name_len=%d",
  95                                 error_msg, (unsigned) (offset % size),
  96                                 offset, le32_to_cpu(de->inode),
  97                                 rlen, de->name_len);
  98
  99         return 1;
 100 }
 101
 102 static int ext4_readdir(struct file *file, struct dir_context *ctx)
 103 {
 104         unsigned int offset;
 105         int i;
 106         struct ext4_dir_entry_2 *de;
 107         int err;
 108         struct inode *inode = file_inode(file);
 109         struct super_block *sb = inode->i_sb;
 110         struct buffer_head *bh = NULL;
 111         int dir_has_error = 0;
 112         struct fscrypt_str fstr = FSTR_INIT(NULL, 0);
 113
 114         if (ext4_encrypted_inode(inode)) {
 115                 err = fscrypt_get_encryption_info(inode);
 116                 if (err && err != -ENOKEY)
 117                         return err;
 118         }
 119
 120         if (is_dx_dir(inode)) {
 121                 err = ext4_dx_readdir(file, ctx);
 122                 if (err != ERR_BAD_DX_DIR) {
 123                         return err;
 124                 }
 125                 /*
 126                  * We don't set the inode dirty flag since it's not
 127                  * critical that it get flushed back to the disk.
 128                  */
 129                 ext4_clear_inode_flag(file_inode(file),
 130                                       EXT4_INODE_INDEX);
 131         }
 132
 133         if (ext4_has_inline_data(inode)) {
 134                 int has_inline_data = 1;
 135                 err = ext4_read_inline_dir(file, ctx,
 136                                            &has_inline_data);
 137                 if (has_inline_data)
 138                         return err;
 139         }
 140
 141         if (ext4_encrypted_inode(inode)) {
 142                 err = fscrypt_fname_alloc_buffer(inode, EXT4_NAME_LEN, &fstr);
 143                 if (err < 0)
 144                         return err;
 145         }
 146
 147         offset = ctx->pos & (sb->s_blocksize - 1);
 148
 149         while (ctx->pos < inode->i_size) {
 150                 struct ext4_map_blocks map;
 151
 152                 if (fatal_signal_pending(current)) {
 153                         err = -ERESTARTSYS;
 154                         goto errout;
 155                 }
 156                 cond_resched();
 157                 map.m_lblk = ctx->pos >> EXT4_BLOCK_SIZE_BITS(sb);
 158                 map.m_len = 1;
 159                 err = ext4_map_blocks(NULL, inode, &map, 0);
 160                 if (err > 0) {
 161                         pgoff_t index = map.m_pblk >>
 162                                         (PAGE_SHIFT - inode->i_blkbits);
 163                         if (!ra_has_index(&file->f_ra, index))
 164                                 page_cache_sync_readahead(
 165                                         sb->s_bdev->bd_inode->i_mapping,
 166                                         &file->f_ra, file,
 167                                         index, 1);
 168                         file->f_ra.prev_pos = (loff_t)index << PAGE_SHIFT;
 169                         bh = ext4_bread(NULL, inode, map.m_lblk, 0);
 170                         if (IS_ERR(bh)) {
 171                                 err = PTR_ERR(bh);
 172                                 bh = NULL;
 173                                 goto errout;
 174                         }
 175                 }
 176
 177                 if (!bh) {
 178                         if (!dir_has_error) {
 179                                 EXT4_ERROR_FILE(file, 0,
 180                                                 "directory contains a "
 181                                                 "hole at offset %llu",
 182                                            (unsigned long long) ctx->pos);
 183                                 dir_has_error = 1;
 184                         }
 185                         /* corrupt size?  Maybe no more blocks to read */
 186                         if (ctx->pos > inode->i_blocks << 9)
 187                                 break;
 188                         ctx->pos += sb->s_blocksize - offset;
 189                         continue;
 190                 }
 191
 192                 /* Check the checksum */
 193                 if (!buffer_verified(bh) &&
 194                     !ext4_dirent_csum_verify(inode,
 195                                 (struct ext4_dir_entry *)bh->b_data)) {
 196                         EXT4_ERROR_FILE(file, 0, "directory fails checksum "
 197                                         "at offset %llu",
 198                                         (unsigned long long)ctx->pos);
 199                         ctx->pos += sb->s_blocksize - offset;
 200                         brelse(bh);
 201                         bh = NULL;
 202                         continue;
 203                 }
 204                 set_buffer_verified(bh);
 205
 206                 /* If the dir block has changed since the last call to
 207                  * readdir(2), then we might be pointing to an invalid
 208                  * dirent right now.  Scan from the start of the block
 209                  * to make sure. */
 210                 if (file->f_version != inode->i_version) {
 211                         for (i = 0; i < sb->s_blocksize && i < offset; ) {
 212                                 de = (struct ext4_dir_entry_2 *)
 213                                         (bh->b_data + i);
 214                                 /* It's too expensive to do a full
 215                                  * dirent test each time round this
 216                                  * loop, but we do have to test at
 217                                  * least that it is non-zero.  A
 218                                  * failure will be detected in the
 219                                  * dirent test below. */
 220                                 if (ext4_rec_len_from_disk(de->rec_len,
 221                                         sb->s_blocksize) < EXT4_DIR_REC_LEN(1))
 222                                         break;
 223                                 i += ext4_rec_len_from_disk(de->rec_len,
 224                                                             sb->s_blocksize);
 225                         }
 226                         offset = i;
 227                         ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1))
 228                                 | offset;
 229                         file->f_version = inode->i_version;
 230                 }
 231
 232                 while (ctx->pos < inode->i_size
 233                        && offset < sb->s_blocksize) {
 234                         de = (struct ext4_dir_entry_2 *) (bh->b_data + offset);
 235                         if (ext4_check_dir_entry(inode, file, de, bh,
 236                                                  bh->b_data, bh->b_size,
 237                                                  offset)) {
 238                                 /*
 239                                  * On error, skip to the next block
 240                                  */
 241                                 ctx->pos = (ctx->pos |
 242                                                 (sb->s_blocksize - 1)) + 1;
 243                                 break;
 244                         }
 245                         offset += ext4_rec_len_from_disk(de->rec_len,
 246                                         sb->s_blocksize);
 247                         if (le32_to_cpu(de->inode)) {
 248                                 if (!ext4_encrypted_inode(inode)) {
 249                                         if (!dir_emit(ctx, de->name,
 250                                             de->name_len,
 251                                             le32_to_cpu(de->inode),
 252                                             get_dtype(sb, de->file_type)))
 253                                                 goto done;
 254                                 } else {
 255                                         int save_len = fstr.len;
 256                                         struct fscrypt_str de_name =
 257                                                         FSTR_INIT(de->name,
 258                                                                 de->name_len);
 259
 260                                         /* Directory is encrypted */
 261                                         err = fscrypt_fname_disk_to_usr(inode,
 262                                                 0, 0, &de_name, &fstr);
 263                                         fstr.len = save_len;
 264                                         if (err < 0)
 265                                                 goto errout;
 266                                         if (!dir_emit(ctx,
 267                                             fstr.name, err,
 268                                             le32_to_cpu(de->inode),
 269                                             get_dtype(sb, de->file_type)))
 270                                                 goto done;
 271                                 }
 272                         }
 273                         ctx->pos += ext4_rec_len_from_disk(de->rec_len,
 274                                                 sb->s_blocksize);
 275                 }
 276                 if ((ctx->pos < inode->i_size) && !dir_relax_shared(inode))
 277                         goto done;
 278                 brelse(bh);
 279                 bh = NULL;
 280                 offset = 0;
 281         }
 282 done:
 283         err = 0;
 284 errout:
 285 #ifdef CONFIG_EXT4_FS_ENCRYPTION
 286         fscrypt_fname_free_buffer(&fstr);
 287 #endif
 288         brelse(bh);
 289         return err;
 290 }
 291
 292 static inline int is_32bit_api(void)
 293 {
 294 #ifdef CONFIG_COMPAT
 295         return in_compat_syscall();
 296 #else
 297         return (BITS_PER_LONG == 32);
 298 #endif
 299 }
 300
 301 /*
 302  * These functions convert from the major/minor hash to an f_pos
 303  * value for dx directories
 304  *
 305  * Upper layer (for example NFS) should specify FMODE_32BITHASH or
 306  * FMODE_64BITHASH explicitly. On the other hand, we allow ext4 to be mounted
 307  * directly on both 32-bit and 64-bit nodes, under such case, neither
 308  * FMODE_32BITHASH nor FMODE_64BITHASH is specified.
 309  */
 310 static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor)
 311 {
 312         if ((filp->f_mode & FMODE_32BITHASH) ||
 313             (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
 314                 return major >> 1;
 315         else
 316                 return ((__u64)(major >> 1) << 32) | (__u64)minor;
 317 }
 318
 319 static inline __u32 pos2maj_hash(struct file *filp, loff_t pos)
 320 {
 321         if ((filp->f_mode & FMODE_32BITHASH) ||
 322             (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
 323                 return (pos << 1) & 0xffffffff;
 324         else
 325                 return ((pos >> 32) << 1) & 0xffffffff;
 326 }
 327
 328 static inline __u32 pos2min_hash(struct file *filp, loff_t pos)
 329 {
 330         if ((filp->f_mode & FMODE_32BITHASH) ||
 331             (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
 332                 return 0;
 333         else
 334                 return pos & 0xffffffff;
 335 }
 336
 337 /*
 338  * Return 32- or 64-bit end-of-file for dx directories
 339  */
 340 static inline loff_t ext4_get_htree_eof(struct file *filp)
 341 {
 342         if ((filp->f_mode & FMODE_32BITHASH) ||
 343             (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
 344                 return EXT4_HTREE_EOF_32BIT;
 345         else
 346                 return EXT4_HTREE_EOF_64BIT;
 347 }
 348
 349
 350 /*
 351  * ext4_dir_llseek() calls generic_file_llseek_size to handle htree
 352  * directories, where the "offset" is in terms of the filename hash
 353  * value instead of the byte offset.
 354  *
 355  * Because we may return a 64-bit hash that is well beyond offset limits,
 356  * we need to pass the max hash as the maximum allowable offset in
 357  * the htree directory case.
 358  *
 359  * For non-htree, ext4_llseek already chooses the proper max offset.
 360  */
 361 static loff_t ext4_dir_llseek(struct file *file, loff_t offset, int whence)
 362 {
 363         struct inode *inode = file->f_mapping->host;
 364         int dx_dir = is_dx_dir(inode);
 365         loff_t htree_max = ext4_get_htree_eof(file);
 366
 367         if (likely(dx_dir))
 368                 return generic_file_llseek_size(file, offset, whence,
 369                                                     htree_max, htree_max);
 370         else
 371                 return ext4_llseek(file, offset, whence);
 372 }
 373
 374 /*
 375  * This structure holds the nodes of the red-black tree used to store
 376  * the directory entry in hash order.
 377  */
 378 struct fname {
 379         __u32           hash;
 380         __u32           minor_hash;
 381         struct rb_node  rb_hash;
 382         struct fname    *next;
 383         __u32           inode;
 384         __u8            name_len;
 385         __u8            file_type;
 386         char            name[0];
 387 };
 388
 389 /*
 390  * This functoin implements a non-recursive way of freeing all of the
 391  * nodes in the red-black tree.
 392  */
 393 static void free_rb_tree_fname(struct rb_root *root)
 394 {
 395         struct fname *fname, *next;
 396
 397         rbtree_postorder_for_each_entry_safe(fname, next, root, rb_hash)
 398                 while (fname) {
 399                         struct fname *old = fname;
 400                         fname = fname->next;
 401                         kfree(old);
 402                 }
 403
 404         *root = RB_ROOT;
 405 }
 406
 407
 408 static struct dir_private_info *ext4_htree_create_dir_info(struct file *filp,
 409                                                            loff_t pos)
 410 {
 411         struct dir_private_info *p;
 412
 413         p = kzalloc(sizeof(struct dir_private_info), GFP_KERNEL);
 414         if (!p)
 415                 return NULL;
 416         p->curr_hash = pos2maj_hash(filp, pos);
 417         p->curr_minor_hash = pos2min_hash(filp, pos);
 418         return p;
 419 }
 420
 421 void ext4_htree_free_dir_info(struct dir_private_info *p)
 422 {
 423         free_rb_tree_fname(&p->root);
 424         kfree(p);
 425 }
 426
 427 /*
 428  * Given a directory entry, enter it into the fname rb tree.
 429  *
 430  * When filename encryption is enabled, the dirent will hold the
 431  * encrypted filename, while the htree will hold decrypted filename.
 432  * The decrypted filename is passed in via ent_name.  parameter.
 433  */
 434 int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
 435                              __u32 minor_hash,
 436                             struct ext4_dir_entry_2 *dirent,
 437                             struct fscrypt_str *ent_name)
 438 {
 439         struct rb_node **p, *parent = NULL;
 440         struct fname *fname, *new_fn;
 441         struct dir_private_info *info;
 442         int len;
 443
 444         info = dir_file->private_data;
 445         p = &info->root.rb_node;
 446
 447         /* Create and allocate the fname structure */
 448         len = sizeof(struct fname) + ent_name->len + 1;
 449         new_fn = kzalloc(len, GFP_KERNEL);
 450         if (!new_fn)
 451                 return -ENOMEM;
 452         new_fn->hash = hash;
 453         new_fn->minor_hash = minor_hash;
 454         new_fn->inode = le32_to_cpu(dirent->inode);
 455         new_fn->name_len = ent_name->len;
 456         new_fn->file_type = dirent->file_type;
 457         memcpy(new_fn->name, ent_name->name, ent_name->len);
 458         new_fn->name[ent_name->len] = 0;
 459
 460         while (*p) {
 461                 parent = *p;
 462                 fname = rb_entry(parent, struct fname, rb_hash);
 463
 464                 /*
 465                  * If the hash and minor hash match up, then we put
 466                  * them on a linked list.  This rarely happens...
 467                  */
 468                 if ((new_fn->hash == fname->hash) &&
 469                     (new_fn->minor_hash == fname->minor_hash)) {
 470                         new_fn->next = fname->next;
 471                         fname->next = new_fn;
 472                         return 0;
 473                 }
 474
 475                 if (new_fn->hash < fname->hash)
 476                         p = &(*p)->rb_left;
 477                 else if (new_fn->hash > fname->hash)
 478                         p = &(*p)->rb_right;
 479                 else if (new_fn->minor_hash < fname->minor_hash)
 480                         p = &(*p)->rb_left;
 481                 else /* if (new_fn->minor_hash > fname->minor_hash) */
 482                         p = &(*p)->rb_right;
 483         }
 484
 485         rb_link_node(&new_fn->rb_hash, parent, p);
 486         rb_insert_color(&new_fn->rb_hash, &info->root);
 487         return 0;
 488 }
 489
 490
 491
 492 /*
 493  * This is a helper function for ext4_dx_readdir.  It calls filldir
 494  * for all entres on the fname linked list.  (Normally there is only
 495  * one entry on the linked list, unless there are 62 bit hash collisions.)
 496  */
 497 static int call_filldir(struct file *file, struct dir_context *ctx,
 498                         struct fname *fname)
 499 {
 500         struct dir_private_info *info = file->private_data;
 501         struct inode *inode = file_inode(file);
 502         struct super_block *sb = inode->i_sb;
 503
 504         if (!fname) {
 505                 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: comm %s: "
 506                          "called with null fname?!?", __func__, __LINE__,
 507                          inode->i_ino, current->comm);
 508                 return 0;
 509         }
 510         ctx->pos = hash2pos(file, fname->hash, fname->minor_hash);
 511         while (fname) {
 512                 if (!dir_emit(ctx, fname->name,
 513                                 fname->name_len,
 514                                 fname->inode,
 515                                 get_dtype(sb, fname->file_type))) {
 516                         info->extra_fname = fname;
 517                         return 1;
 518                 }
 519                 fname = fname->next;
 520         }
 521         return 0;
 522 }
 523
 524 static int ext4_dx_readdir(struct file *file, struct dir_context *ctx)
 525 {
 526         struct dir_private_info *info = file->private_data;
 527         struct inode *inode = file_inode(file);
 528         struct fname *fname;
 529         int     ret;
 530
 531         if (!info) {
 532                 info = ext4_htree_create_dir_info(file, ctx->pos);
 533                 if (!info)
 534                         return -ENOMEM;
 535                 file->private_data = info;
 536         }
 537
 538         if (ctx->pos == ext4_get_htree_eof(file))
 539                 return 0;       /* EOF */
 540
 541         /* Some one has messed with f_pos; reset the world */
 542         if (info->last_pos != ctx->pos) {
 543                 free_rb_tree_fname(&info->root);
 544                 info->curr_node = NULL;
 545                 info->extra_fname = NULL;
 546                 info->curr_hash = pos2maj_hash(file, ctx->pos);
 547                 info->curr_minor_hash = pos2min_hash(file, ctx->pos);
 548         }
 549
 550         /*
 551          * If there are any leftover names on the hash collision
 552          * chain, return them first.
 553          */
 554         if (info->extra_fname) {
 555                 if (call_filldir(file, ctx, info->extra_fname))
 556                         goto finished;
 557                 info->extra_fname = NULL;
 558                 goto next_node;
 559         } else if (!info->curr_node)
 560                 info->curr_node = rb_first(&info->root);
 561
 562         while (1) {
 563                 /*
 564                  * Fill the rbtree if we have no more entries,
 565                  * or the inode has changed since we last read in the
 566                  * cached entries.
 567                  */
 568                 if ((!info->curr_node) ||
 569                     (file->f_version != inode->i_version)) {
 570                         info->curr_node = NULL;
 571                         free_rb_tree_fname(&info->root);
 572                         file->f_version = inode->i_version;
 573                         ret = ext4_htree_fill_tree(file, info->curr_hash,
 574                                                    info->curr_minor_hash,
 575                                                    &info->next_hash);
 576                         if (ret < 0)
 577                                 return ret;
 578                         if (ret == 0) {
 579                                 ctx->pos = ext4_get_htree_eof(file);
 580                                 break;
 581                         }
 582                         info->curr_node = rb_first(&info->root);
 583                 }
 584
 585                 fname = rb_entry(info->curr_node, struct fname, rb_hash);
 586                 info->curr_hash = fname->hash;
 587                 info->curr_minor_hash = fname->minor_hash;
 588                 if (call_filldir(file, ctx, fname))
 589                         break;
 590         next_node:
 591                 info->curr_node = rb_next(info->curr_node);
 592                 if (info->curr_node) {
 593                         fname = rb_entry(info->curr_node, struct fname,
 594                                          rb_hash);
 595                         info->curr_hash = fname->hash;
 596                         info->curr_minor_hash = fname->minor_hash;
 597                 } else {
 598                         if (info->next_hash == ~0) {
 599                                 ctx->pos = ext4_get_htree_eof(file);
 600                                 break;
 601                         }
 602                         info->curr_hash = info->next_hash;
 603                         info->curr_minor_hash = 0;
 604                 }
 605         }
 606 finished:
 607         info->last_pos = ctx->pos;
 608         return 0;
 609 }
 610
 611 static int ext4_dir_open(struct inode * inode, struct file * filp)
 612 {
 613         if (ext4_encrypted_inode(inode))
 614                 return fscrypt_get_encryption_info(inode) ? -EACCES : 0;
 615         return 0;
 616 }
 617
 618 static int ext4_release_dir(struct inode *inode, struct file *filp)
 619 {
 620         if (filp->private_data)
 621                 ext4_htree_free_dir_info(filp->private_data);
 622
 623         return 0;
 624 }
 625
 626 int ext4_check_all_de(struct inode *dir, struct buffer_head *bh, void *buf,
 627                       int buf_size)
 628 {
 629         struct ext4_dir_entry_2 *de;
 630         int nlen, rlen;
 631         unsigned int offset = 0;
 632         char *top;
 633
 634         de = (struct ext4_dir_entry_2 *)buf;
 635         top = buf + buf_size;
 636         while ((char *) de < top) {
 637                 if (ext4_check_dir_entry(dir, NULL, de, bh,
 638                                          buf, buf_size, offset))
 639                         return -EFSCORRUPTED;
 640                 nlen = EXT4_DIR_REC_LEN(de->name_len);
 641                 rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
 642                 de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
 643                 offset += rlen;
 644         }
 645         if ((char *) de > top)
 646                 return -EFSCORRUPTED;
 647
 648         return 0;
 649 }
 650
 651 const struct file_operations ext4_dir_operations = {
 652         .llseek         = ext4_dir_llseek,
 653         .read           = generic_read_dir,
 654         .iterate_shared = ext4_readdir,
 655         .unlocked_ioctl = ext4_ioctl,
 656 #ifdef CONFIG_COMPAT
 657         .compat_ioctl   = ext4_compat_ioctl,
 658 #endif
 659         .fsync          = ext4_sync_file,
 660         .open           = ext4_dir_open,
 661         .release        = ext4_release_dir,
 662 };