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 ext4_str fname_crypto_str = {.name = NULL, .len = 0};
 113
 114         if (ext4_encrypted_inode(inode)) {
 115                 err = ext4_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 = ext4_fname_crypto_alloc_buffer(inode, EXT4_NAME_LEN,
 143                                                      &fname_crypto_str);
 144                 if (err < 0)
 145                         return err;
 146         }
 147
 148         offset = ctx->pos & (sb->s_blocksize - 1);
 149
 150         while (ctx->pos < inode->i_size) {
 151                 struct ext4_map_blocks map;
 152
 153                 map.m_lblk = ctx->pos >> EXT4_BLOCK_SIZE_BITS(sb);
 154                 map.m_len = 1;
 155                 err = ext4_map_blocks(NULL, inode, &map, 0);
 156                 if (err > 0) {
 157                         pgoff_t index = map.m_pblk >>
 158                                         (PAGE_CACHE_SHIFT - inode->i_blkbits);
 159                         if (!ra_has_index(&file->f_ra, index))
 160                                 page_cache_sync_readahead(
 161                                         sb->s_bdev->bd_inode->i_mapping,
 162                                         &file->f_ra, file,
 163                                         index, 1);
 164                         file->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT;
 165                         bh = ext4_bread(NULL, inode, map.m_lblk, 0);
 166                         if (IS_ERR(bh)) {
 167                                 err = PTR_ERR(bh);
 168                                 bh = NULL;
 169                                 goto errout;
 170                         }
 171                 }
 172
 173                 if (!bh) {
 174                         if (!dir_has_error) {
 175                                 EXT4_ERROR_FILE(file, 0,
 176                                                 "directory contains a "
 177                                                 "hole at offset %llu",
 178                                            (unsigned long long) ctx->pos);
 179                                 dir_has_error = 1;
 180                         }
 181                         /* corrupt size?  Maybe no more blocks to read */
 182                         if (ctx->pos > inode->i_blocks << 9)
 183                                 break;
 184                         ctx->pos += sb->s_blocksize - offset;
 185                         continue;
 186                 }
 187
 188                 /* Check the checksum */
 189                 if (!buffer_verified(bh) &&
 190                     !ext4_dirent_csum_verify(inode,
 191                                 (struct ext4_dir_entry *)bh->b_data)) {
 192                         EXT4_ERROR_FILE(file, 0, "directory fails checksum "
 193                                         "at offset %llu",
 194                                         (unsigned long long)ctx->pos);
 195                         ctx->pos += sb->s_blocksize - offset;
 196                         brelse(bh);
 197                         bh = NULL;
 198                         continue;
 199                 }
 200                 set_buffer_verified(bh);
 201
 202                 /* If the dir block has changed since the last call to
 203                  * readdir(2), then we might be pointing to an invalid
 204                  * dirent right now.  Scan from the start of the block
 205                  * to make sure. */
 206                 if (file->f_version != inode->i_version) {
 207                         for (i = 0; i < sb->s_blocksize && i < offset; ) {
 208                                 de = (struct ext4_dir_entry_2 *)
 209                                         (bh->b_data + i);
 210                                 /* It's too expensive to do a full
 211                                  * dirent test each time round this
 212                                  * loop, but we do have to test at
 213                                  * least that it is non-zero.  A
 214                                  * failure will be detected in the
 215                                  * dirent test below. */
 216                                 if (ext4_rec_len_from_disk(de->rec_len,
 217                                         sb->s_blocksize) < EXT4_DIR_REC_LEN(1))
 218                                         break;
 219                                 i += ext4_rec_len_from_disk(de->rec_len,
 220                                                             sb->s_blocksize);
 221                         }
 222                         offset = i;
 223                         ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1))
 224                                 | offset;
 225                         file->f_version = inode->i_version;
 226                 }
 227
 228                 while (ctx->pos < inode->i_size
 229                        && offset < sb->s_blocksize) {
 230                         de = (struct ext4_dir_entry_2 *) (bh->b_data + offset);
 231                         if (ext4_check_dir_entry(inode, file, de, bh,
 232                                                  bh->b_data, bh->b_size,
 233                                                  offset)) {
 234                                 /*
 235                                  * On error, skip to the next block
 236                                  */
 237                                 ctx->pos = (ctx->pos |
 238                                                 (sb->s_blocksize - 1)) + 1;
 239                                 break;
 240                         }
 241                         offset += ext4_rec_len_from_disk(de->rec_len,
 242                                         sb->s_blocksize);
 243                         if (le32_to_cpu(de->inode)) {
 244                                 if (!ext4_encrypted_inode(inode)) {
 245                                         if (!dir_emit(ctx, de->name,
 246                                             de->name_len,
 247                                             le32_to_cpu(de->inode),
 248                                             get_dtype(sb, de->file_type)))
 249                                                 goto done;
 250                                 } else {
 251                                         int save_len = fname_crypto_str.len;
 252
 253                                         /* Directory is encrypted */
 254                                         err = ext4_fname_disk_to_usr(inode,
 255                                                 NULL, de, &fname_crypto_str);
 256                                         fname_crypto_str.len = save_len;
 257                                         if (err < 0)
 258                                                 goto errout;
 259                                         if (!dir_emit(ctx,
 260                                             fname_crypto_str.name, err,
 261                                             le32_to_cpu(de->inode),
 262                                             get_dtype(sb, de->file_type)))
 263                                                 goto done;
 264                                 }
 265                         }
 266                         ctx->pos += ext4_rec_len_from_disk(de->rec_len,
 267                                                 sb->s_blocksize);
 268                 }
 269                 if ((ctx->pos < inode->i_size) && !dir_relax(inode))
 270                         goto done;
 271                 brelse(bh);
 272                 bh = NULL;
 273                 offset = 0;
 274         }
 275 done:
 276         err = 0;
 277 errout:
 278 #ifdef CONFIG_EXT4_FS_ENCRYPTION
 279         ext4_fname_crypto_free_buffer(&fname_crypto_str);
 280 #endif
 281         brelse(bh);
 282         return err;
 283 }
 284
 285 static inline int is_32bit_api(void)
 286 {
 287 #ifdef CONFIG_COMPAT
 288         return in_compat_syscall();
 289 #else
 290         return (BITS_PER_LONG == 32);
 291 #endif
 292 }
 293
 294 /*
 295  * These functions convert from the major/minor hash to an f_pos
 296  * value for dx directories
 297  *
 298  * Upper layer (for example NFS) should specify FMODE_32BITHASH or
 299  * FMODE_64BITHASH explicitly. On the other hand, we allow ext4 to be mounted
 300  * directly on both 32-bit and 64-bit nodes, under such case, neither
 301  * FMODE_32BITHASH nor FMODE_64BITHASH is specified.
 302  */
 303 static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor)
 304 {
 305         if ((filp->f_mode & FMODE_32BITHASH) ||
 306             (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
 307                 return major >> 1;
 308         else
 309                 return ((__u64)(major >> 1) << 32) | (__u64)minor;
 310 }
 311
 312 static inline __u32 pos2maj_hash(struct file *filp, loff_t pos)
 313 {
 314         if ((filp->f_mode & FMODE_32BITHASH) ||
 315             (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
 316                 return (pos << 1) & 0xffffffff;
 317         else
 318                 return ((pos >> 32) << 1) & 0xffffffff;
 319 }
 320
 321 static inline __u32 pos2min_hash(struct file *filp, loff_t pos)
 322 {
 323         if ((filp->f_mode & FMODE_32BITHASH) ||
 324             (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
 325                 return 0;
 326         else
 327                 return pos & 0xffffffff;
 328 }
 329
 330 /*
 331  * Return 32- or 64-bit end-of-file for dx directories
 332  */
 333 static inline loff_t ext4_get_htree_eof(struct file *filp)
 334 {
 335         if ((filp->f_mode & FMODE_32BITHASH) ||
 336             (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
 337                 return EXT4_HTREE_EOF_32BIT;
 338         else
 339                 return EXT4_HTREE_EOF_64BIT;
 340 }
 341
 342
 343 /*
 344  * ext4_dir_llseek() calls generic_file_llseek_size to handle htree
 345  * directories, where the "offset" is in terms of the filename hash
 346  * value instead of the byte offset.
 347  *
 348  * Because we may return a 64-bit hash that is well beyond offset limits,
 349  * we need to pass the max hash as the maximum allowable offset in
 350  * the htree directory case.
 351  *
 352  * For non-htree, ext4_llseek already chooses the proper max offset.
 353  */
 354 static loff_t ext4_dir_llseek(struct file *file, loff_t offset, int whence)
 355 {
 356         struct inode *inode = file->f_mapping->host;
 357         int dx_dir = is_dx_dir(inode);
 358         loff_t htree_max = ext4_get_htree_eof(file);
 359
 360         if (likely(dx_dir))
 361                 return generic_file_llseek_size(file, offset, whence,
 362                                                     htree_max, htree_max);
 363         else
 364                 return ext4_llseek(file, offset, whence);
 365 }
 366
 367 /*
 368  * This structure holds the nodes of the red-black tree used to store
 369  * the directory entry in hash order.
 370  */
 371 struct fname {
 372         __u32           hash;
 373         __u32           minor_hash;
 374         struct rb_node  rb_hash;
 375         struct fname    *next;
 376         __u32           inode;
 377         __u8            name_len;
 378         __u8            file_type;
 379         char            name[0];
 380 };
 381
 382 /*
 383  * This functoin implements a non-recursive way of freeing all of the
 384  * nodes in the red-black tree.
 385  */
 386 static void free_rb_tree_fname(struct rb_root *root)
 387 {
 388         struct fname *fname, *next;
 389
 390         rbtree_postorder_for_each_entry_safe(fname, next, root, rb_hash)
 391                 while (fname) {
 392                         struct fname *old = fname;
 393                         fname = fname->next;
 394                         kfree(old);
 395                 }
 396
 397         *root = RB_ROOT;
 398 }
 399
 400
 401 static struct dir_private_info *ext4_htree_create_dir_info(struct file *filp,
 402                                                            loff_t pos)
 403 {
 404         struct dir_private_info *p;
 405
 406         p = kzalloc(sizeof(struct dir_private_info), GFP_KERNEL);
 407         if (!p)
 408                 return NULL;
 409         p->curr_hash = pos2maj_hash(filp, pos);
 410         p->curr_minor_hash = pos2min_hash(filp, pos);
 411         return p;
 412 }
 413
 414 void ext4_htree_free_dir_info(struct dir_private_info *p)
 415 {
 416         free_rb_tree_fname(&p->root);
 417         kfree(p);
 418 }
 419
 420 /*
 421  * Given a directory entry, enter it into the fname rb tree.
 422  *
 423  * When filename encryption is enabled, the dirent will hold the
 424  * encrypted filename, while the htree will hold decrypted filename.
 425  * The decrypted filename is passed in via ent_name.  parameter.
 426  */
 427 int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
 428                              __u32 minor_hash,
 429                             struct ext4_dir_entry_2 *dirent,
 430                             struct ext4_str *ent_name)
 431 {
 432         struct rb_node **p, *parent = NULL;
 433         struct fname *fname, *new_fn;
 434         struct dir_private_info *info;
 435         int len;
 436
 437         info = dir_file->private_data;
 438         p = &info->root.rb_node;
 439
 440         /* Create and allocate the fname structure */
 441         len = sizeof(struct fname) + ent_name->len + 1;
 442         new_fn = kzalloc(len, GFP_KERNEL);
 443         if (!new_fn)
 444                 return -ENOMEM;
 445         new_fn->hash = hash;
 446         new_fn->minor_hash = minor_hash;
 447         new_fn->inode = le32_to_cpu(dirent->inode);
 448         new_fn->name_len = ent_name->len;
 449         new_fn->file_type = dirent->file_type;
 450         memcpy(new_fn->name, ent_name->name, ent_name->len);
 451         new_fn->name[ent_name->len] = 0;
 452
 453         while (*p) {
 454                 parent = *p;
 455                 fname = rb_entry(parent, struct fname, rb_hash);
 456
 457                 /*
 458                  * If the hash and minor hash match up, then we put
 459                  * them on a linked list.  This rarely happens...
 460                  */
 461                 if ((new_fn->hash == fname->hash) &&
 462                     (new_fn->minor_hash == fname->minor_hash)) {
 463                         new_fn->next = fname->next;
 464                         fname->next = new_fn;
 465                         return 0;
 466                 }
 467
 468                 if (new_fn->hash < fname->hash)
 469                         p = &(*p)->rb_left;
 470                 else if (new_fn->hash > fname->hash)
 471                         p = &(*p)->rb_right;
 472                 else if (new_fn->minor_hash < fname->minor_hash)
 473                         p = &(*p)->rb_left;
 474                 else /* if (new_fn->minor_hash > fname->minor_hash) */
 475                         p = &(*p)->rb_right;
 476         }
 477
 478         rb_link_node(&new_fn->rb_hash, parent, p);
 479         rb_insert_color(&new_fn->rb_hash, &info->root);
 480         return 0;
 481 }
 482
 483
 484
 485 /*
 486  * This is a helper function for ext4_dx_readdir.  It calls filldir
 487  * for all entres on the fname linked list.  (Normally there is only
 488  * one entry on the linked list, unless there are 62 bit hash collisions.)
 489  */
 490 static int call_filldir(struct file *file, struct dir_context *ctx,
 491                         struct fname *fname)
 492 {
 493         struct dir_private_info *info = file->private_data;
 494         struct inode *inode = file_inode(file);
 495         struct super_block *sb = inode->i_sb;
 496
 497         if (!fname) {
 498                 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: comm %s: "
 499                          "called with null fname?!?", __func__, __LINE__,
 500                          inode->i_ino, current->comm);
 501                 return 0;
 502         }
 503         ctx->pos = hash2pos(file, fname->hash, fname->minor_hash);
 504         while (fname) {
 505                 if (!dir_emit(ctx, fname->name,
 506                                 fname->name_len,
 507                                 fname->inode,
 508                                 get_dtype(sb, fname->file_type))) {
 509                         info->extra_fname = fname;
 510                         return 1;
 511                 }
 512                 fname = fname->next;
 513         }
 514         return 0;
 515 }
 516
 517 static int ext4_dx_readdir(struct file *file, struct dir_context *ctx)
 518 {
 519         struct dir_private_info *info = file->private_data;
 520         struct inode *inode = file_inode(file);
 521         struct fname *fname;
 522         int     ret;
 523
 524         if (!info) {
 525                 info = ext4_htree_create_dir_info(file, ctx->pos);
 526                 if (!info)
 527                         return -ENOMEM;
 528                 file->private_data = info;
 529         }
 530
 531         if (ctx->pos == ext4_get_htree_eof(file))
 532                 return 0;       /* EOF */
 533
 534         /* Some one has messed with f_pos; reset the world */
 535         if (info->last_pos != ctx->pos) {
 536                 free_rb_tree_fname(&info->root);
 537                 info->curr_node = NULL;
 538                 info->extra_fname = NULL;
 539                 info->curr_hash = pos2maj_hash(file, ctx->pos);
 540                 info->curr_minor_hash = pos2min_hash(file, ctx->pos);
 541         }
 542
 543         /*
 544          * If there are any leftover names on the hash collision
 545          * chain, return them first.
 546          */
 547         if (info->extra_fname) {
 548                 if (call_filldir(file, ctx, info->extra_fname))
 549                         goto finished;
 550                 info->extra_fname = NULL;
 551                 goto next_node;
 552         } else if (!info->curr_node)
 553                 info->curr_node = rb_first(&info->root);
 554
 555         while (1) {
 556                 /*
 557                  * Fill the rbtree if we have no more entries,
 558                  * or the inode has changed since we last read in the
 559                  * cached entries.
 560                  */
 561                 if ((!info->curr_node) ||
 562                     (file->f_version != inode->i_version)) {
 563                         info->curr_node = NULL;
 564                         free_rb_tree_fname(&info->root);
 565                         file->f_version = inode->i_version;
 566                         ret = ext4_htree_fill_tree(file, info->curr_hash,
 567                                                    info->curr_minor_hash,
 568                                                    &info->next_hash);
 569                         if (ret < 0)
 570                                 return ret;
 571                         if (ret == 0) {
 572                                 ctx->pos = ext4_get_htree_eof(file);
 573                                 break;
 574                         }
 575                         info->curr_node = rb_first(&info->root);
 576                 }
 577
 578                 fname = rb_entry(info->curr_node, struct fname, rb_hash);
 579                 info->curr_hash = fname->hash;
 580                 info->curr_minor_hash = fname->minor_hash;
 581                 if (call_filldir(file, ctx, fname))
 582                         break;
 583         next_node:
 584                 info->curr_node = rb_next(info->curr_node);
 585                 if (info->curr_node) {
 586                         fname = rb_entry(info->curr_node, struct fname,
 587                                          rb_hash);
 588                         info->curr_hash = fname->hash;
 589                         info->curr_minor_hash = fname->minor_hash;
 590                 } else {
 591                         if (info->next_hash == ~0) {
 592                                 ctx->pos = ext4_get_htree_eof(file);
 593                                 break;
 594                         }
 595                         info->curr_hash = info->next_hash;
 596                         info->curr_minor_hash = 0;
 597                 }
 598         }
 599 finished:
 600         info->last_pos = ctx->pos;
 601         return 0;
 602 }
 603
 604 static int ext4_dir_open(struct inode * inode, struct file * filp)
 605 {
 606         if (ext4_encrypted_inode(inode))
 607                 return ext4_get_encryption_info(inode) ? -EACCES : 0;
 608         return 0;
 609 }
 610
 611 static int ext4_release_dir(struct inode *inode, struct file *filp)
 612 {
 613         if (filp->private_data)
 614                 ext4_htree_free_dir_info(filp->private_data);
 615
 616         return 0;
 617 }
 618
 619 int ext4_check_all_de(struct inode *dir, struct buffer_head *bh, void *buf,
 620                       int buf_size)
 621 {
 622         struct ext4_dir_entry_2 *de;
 623         int nlen, rlen;
 624         unsigned int offset = 0;
 625         char *top;
 626
 627         de = (struct ext4_dir_entry_2 *)buf;
 628         top = buf + buf_size;
 629         while ((char *) de < top) {
 630                 if (ext4_check_dir_entry(dir, NULL, de, bh,
 631                                          buf, buf_size, offset))
 632                         return -EFSCORRUPTED;
 633                 nlen = EXT4_DIR_REC_LEN(de->name_len);
 634                 rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
 635                 de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
 636                 offset += rlen;
 637         }
 638         if ((char *) de > top)
 639                 return -EFSCORRUPTED;
 640
 641         return 0;
 642 }
 643
 644 const struct file_operations ext4_dir_operations = {
 645         .llseek         = ext4_dir_llseek,
 646         .read           = generic_read_dir,
 647         .iterate        = ext4_readdir,
 648         .unlocked_ioctl = ext4_ioctl,
 649 #ifdef CONFIG_COMPAT
 650         .compat_ioctl   = ext4_compat_ioctl,
 651 #endif
 652         .fsync          = ext4_sync_file,
 653         .open           = ext4_dir_open,
 654         .release        = ext4_release_dir,
 655 };