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/jbd2.h>
  26 #include <linux/buffer_head.h>
  27 #include <linux/slab.h>
  28 #include <linux/rbtree.h>
  29 #include "ext4.h"
  30
  31 static unsigned char ext4_filetype_table[] = {
  32         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
  33 };
  34
  35 static int ext4_dx_readdir(struct file *filp,
  36                            void *dirent, filldir_t filldir);
  37
  38 static unsigned char get_dtype(struct super_block *sb, int filetype)
  39 {
  40         if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FILETYPE) ||
  41             (filetype >= EXT4_FT_MAX))
  42                 return DT_UNKNOWN;
  43
  44         return (ext4_filetype_table[filetype]);
  45 }
  46
  47 /**
  48  * Check if the given dir-inode refers to an htree-indexed directory
  49  * (or a directory which chould potentially get coverted to use htree
  50  * indexing).
  51  *
  52  * Return 1 if it is a dx dir, 0 if not
  53  */
  54 static int is_dx_dir(struct inode *inode)
  55 {
  56         struct super_block *sb = inode->i_sb;
  57
  58         if (EXT4_HAS_COMPAT_FEATURE(inode->i_sb,
  59                      EXT4_FEATURE_COMPAT_DIR_INDEX) &&
  60             ((ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) ||
  61              ((inode->i_size >> sb->s_blocksize_bits) == 1)))
  62                 return 1;
  63
  64         return 0;
  65 }
  66
  67 /*
  68  * Return 0 if the directory entry is OK, and 1 if there is a problem
  69  *
  70  * Note: this is the opposite of what ext2 and ext3 historically returned...
  71  */
  72 int __ext4_check_dir_entry(const char *function, unsigned int line,
  73                            struct inode *dir, struct file *filp,
  74                            struct ext4_dir_entry_2 *de,
  75                            struct buffer_head *bh,
  76                            unsigned int offset)
  77 {
  78         const char *error_msg = NULL;
  79         const int rlen = ext4_rec_len_from_disk(de->rec_len,
  80                                                 dir->i_sb->s_blocksize);
  81
  82         if (unlikely(rlen < EXT4_DIR_REC_LEN(1)))
  83                 error_msg = "rec_len is smaller than minimal";
  84         else if (unlikely(rlen % 4 != 0))
  85                 error_msg = "rec_len % 4 != 0";
  86         else if (unlikely(rlen < EXT4_DIR_REC_LEN(de->name_len)))
  87                 error_msg = "rec_len is too small for name_len";
  88         else if (unlikely(((char *) de - bh->b_data) + rlen >
  89                           dir->i_sb->s_blocksize))
  90                 error_msg = "directory entry across blocks";
  91         else if (unlikely(le32_to_cpu(de->inode) >
  92                         le32_to_cpu(EXT4_SB(dir->i_sb)->s_es->s_inodes_count)))
  93                 error_msg = "inode out of bounds";
  94         else
  95                 return 0;
  96
  97         if (filp)
  98                 ext4_error_file(filp, function, line, bh ? bh->b_blocknr : 0,
  99                                 "bad entry in directory: %s - offset=%u(%u), "
 100                                 "inode=%u, rec_len=%d, name_len=%d",
 101                                 error_msg, (unsigned) (offset%bh->b_size),
 102                                 offset, le32_to_cpu(de->inode),
 103                                 rlen, de->name_len);
 104         else
 105                 ext4_error_inode(dir, function, line, bh ? bh->b_blocknr : 0,
 106                                 "bad entry in directory: %s - offset=%u(%u), "
 107                                 "inode=%u, rec_len=%d, name_len=%d",
 108                                 error_msg, (unsigned) (offset%bh->b_size),
 109                                 offset, le32_to_cpu(de->inode),
 110                                 rlen, de->name_len);
 111
 112         return 1;
 113 }
 114
 115 static int ext4_readdir(struct file *filp,
 116                          void *dirent, filldir_t filldir)
 117 {
 118         int error = 0;
 119         unsigned int offset;
 120         int i, stored;
 121         struct ext4_dir_entry_2 *de;
 122         int err;
 123         struct inode *inode = filp->f_path.dentry->d_inode;
 124         struct super_block *sb = inode->i_sb;
 125         int ret = 0;
 126         int dir_has_error = 0;
 127
 128         if (is_dx_dir(inode)) {
 129                 err = ext4_dx_readdir(filp, dirent, filldir);
 130                 if (err != ERR_BAD_DX_DIR) {
 131                         ret = err;
 132                         goto out;
 133                 }
 134                 /*
 135                  * We don't set the inode dirty flag since it's not
 136                  * critical that it get flushed back to the disk.
 137                  */
 138                 ext4_clear_inode_flag(filp->f_path.dentry->d_inode,
 139                                       EXT4_INODE_INDEX);
 140         }
 141         stored = 0;
 142         offset = filp->f_pos & (sb->s_blocksize - 1);
 143
 144         while (!error && !stored && filp->f_pos < inode->i_size) {
 145                 struct ext4_map_blocks map;
 146                 struct buffer_head *bh = NULL;
 147
 148                 map.m_lblk = filp->f_pos >> EXT4_BLOCK_SIZE_BITS(sb);
 149                 map.m_len = 1;
 150                 err = ext4_map_blocks(NULL, inode, &map, 0);
 151                 if (err > 0) {
 152                         pgoff_t index = map.m_pblk >>
 153                                         (PAGE_CACHE_SHIFT - inode->i_blkbits);
 154                         if (!ra_has_index(&filp->f_ra, index))
 155                                 page_cache_sync_readahead(
 156                                         sb->s_bdev->bd_inode->i_mapping,
 157                                         &filp->f_ra, filp,
 158                                         index, 1);
 159                         filp->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT;
 160                         bh = ext4_bread(NULL, inode, map.m_lblk, 0, &err);
 161                 }
 162
 163                 /*
 164                  * We ignore I/O errors on directories so users have a chance
 165                  * of recovering data when there's a bad sector
 166                  */
 167                 if (!bh) {
 168                         if (!dir_has_error) {
 169                                 EXT4_ERROR_FILE(filp, 0,
 170                                                 "directory contains a "
 171                                                 "hole at offset %llu",
 172                                            (unsigned long long) filp->f_pos);
 173                                 dir_has_error = 1;
 174                         }
 175                         /* corrupt size?  Maybe no more blocks to read */
 176                         if (filp->f_pos > inode->i_blocks << 9)
 177                                 break;
 178                         filp->f_pos += sb->s_blocksize - offset;
 179                         continue;
 180                 }
 181
 182 revalidate:
 183                 /* If the dir block has changed since the last call to
 184                  * readdir(2), then we might be pointing to an invalid
 185                  * dirent right now.  Scan from the start of the block
 186                  * to make sure. */
 187                 if (filp->f_version != inode->i_version) {
 188                         for (i = 0; i < sb->s_blocksize && i < offset; ) {
 189                                 de = (struct ext4_dir_entry_2 *)
 190                                         (bh->b_data + i);
 191                                 /* It's too expensive to do a full
 192                                  * dirent test each time round this
 193                                  * loop, but we do have to test at
 194                                  * least that it is non-zero.  A
 195                                  * failure will be detected in the
 196                                  * dirent test below. */
 197                                 if (ext4_rec_len_from_disk(de->rec_len,
 198                                         sb->s_blocksize) < EXT4_DIR_REC_LEN(1))
 199                                         break;
 200                                 i += ext4_rec_len_from_disk(de->rec_len,
 201                                                             sb->s_blocksize);
 202                         }
 203                         offset = i;
 204                         filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1))
 205                                 | offset;
 206                         filp->f_version = inode->i_version;
 207                 }
 208
 209                 while (!error && filp->f_pos < inode->i_size
 210                        && offset < sb->s_blocksize) {
 211                         de = (struct ext4_dir_entry_2 *) (bh->b_data + offset);
 212                         if (ext4_check_dir_entry(inode, filp, de,
 213                                                  bh, offset)) {
 214                                 /*
 215                                  * On error, skip the f_pos to the next block
 216                                  */
 217                                 filp->f_pos = (filp->f_pos |
 218                                                 (sb->s_blocksize - 1)) + 1;
 219                                 brelse(bh);
 220                                 ret = stored;
 221                                 goto out;
 222                         }
 223                         offset += ext4_rec_len_from_disk(de->rec_len,
 224                                         sb->s_blocksize);
 225                         if (le32_to_cpu(de->inode)) {
 226                                 /* We might block in the next section
 227                                  * if the data destination is
 228                                  * currently swapped out.  So, use a
 229                                  * version stamp to detect whether or
 230                                  * not the directory has been modified
 231                                  * during the copy operation.
 232                                  */
 233                                 u64 version = filp->f_version;
 234
 235                                 error = filldir(dirent, de->name,
 236                                                 de->name_len,
 237                                                 filp->f_pos,
 238                                                 le32_to_cpu(de->inode),
 239                                                 get_dtype(sb, de->file_type));
 240                                 if (error)
 241                                         break;
 242                                 if (version != filp->f_version)
 243                                         goto revalidate;
 244                                 stored++;
 245                         }
 246                         filp->f_pos += ext4_rec_len_from_disk(de->rec_len,
 247                                                 sb->s_blocksize);
 248                 }
 249                 offset = 0;
 250                 brelse(bh);
 251         }
 252 out:
 253         return ret;
 254 }
 255
 256 static inline int is_32bit_api(void)
 257 {
 258 #ifdef CONFIG_COMPAT
 259         return is_compat_task();
 260 #else
 261         return (BITS_PER_LONG == 32);
 262 #endif
 263 }
 264
 265 /*
 266  * These functions convert from the major/minor hash to an f_pos
 267  * value for dx directories
 268  *
 269  * Upper layer (for example NFS) should specify FMODE_32BITHASH or
 270  * FMODE_64BITHASH explicitly. On the other hand, we allow ext4 to be mounted
 271  * directly on both 32-bit and 64-bit nodes, under such case, neither
 272  * FMODE_32BITHASH nor FMODE_64BITHASH is specified.
 273  */
 274 static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor)
 275 {
 276         if ((filp->f_mode & FMODE_32BITHASH) ||
 277             (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
 278                 return major >> 1;
 279         else
 280                 return ((__u64)(major >> 1) << 32) | (__u64)minor;
 281 }
 282
 283 static inline __u32 pos2maj_hash(struct file *filp, loff_t pos)
 284 {
 285         if ((filp->f_mode & FMODE_32BITHASH) ||
 286             (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
 287                 return (pos << 1) & 0xffffffff;
 288         else
 289                 return ((pos >> 32) << 1) & 0xffffffff;
 290 }
 291
 292 static inline __u32 pos2min_hash(struct file *filp, loff_t pos)
 293 {
 294         if ((filp->f_mode & FMODE_32BITHASH) ||
 295             (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
 296                 return 0;
 297         else
 298                 return pos & 0xffffffff;
 299 }
 300
 301 /*
 302  * Return 32- or 64-bit end-of-file for dx directories
 303  */
 304 static inline loff_t ext4_get_htree_eof(struct file *filp)
 305 {
 306         if ((filp->f_mode & FMODE_32BITHASH) ||
 307             (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
 308                 return EXT4_HTREE_EOF_32BIT;
 309         else
 310                 return EXT4_HTREE_EOF_64BIT;
 311 }
 312
 313
 314 /*
 315  * ext4_dir_llseek() based on generic_file_llseek() to handle both
 316  * non-htree and htree directories, where the "offset" is in terms
 317  * of the filename hash value instead of the byte offset.
 318  *
 319  * NOTE: offsets obtained *before* ext4_set_inode_flag(dir, EXT4_INODE_INDEX)
 320  *       will be invalid once the directory was converted into a dx directory
 321  */
 322 loff_t ext4_dir_llseek(struct file *file, loff_t offset, int origin)
 323 {
 324         struct inode *inode = file->f_mapping->host;
 325         loff_t ret = -EINVAL;
 326         int dx_dir = is_dx_dir(inode);
 327
 328         mutex_lock(&inode->i_mutex);
 329
 330         /* NOTE: relative offsets with dx directories might not work
 331          *       as expected, as it is difficult to figure out the
 332          *       correct offset between dx hashes */
 333
 334         switch (origin) {
 335         case SEEK_END:
 336                 if (unlikely(offset > 0))
 337                         goto out_err; /* not supported for directories */
 338
 339                 /* so only negative offsets are left, does that have a
 340                  * meaning for directories at all? */
 341                 if (dx_dir)
 342                         offset += ext4_get_htree_eof(file);
 343                 else
 344                         offset += inode->i_size;
 345                 break;
 346         case SEEK_CUR:
 347                 /*
 348                  * Here we special-case the lseek(fd, 0, SEEK_CUR)
 349                  * position-querying operation.  Avoid rewriting the "same"
 350                  * f_pos value back to the file because a concurrent read(),
 351                  * write() or lseek() might have altered it
 352                  */
 353                 if (offset == 0) {
 354                         offset = file->f_pos;
 355                         goto out_ok;
 356                 }
 357
 358                 offset += file->f_pos;
 359                 break;
 360         }
 361
 362         if (unlikely(offset < 0))
 363                 goto out_err;
 364
 365         if (!dx_dir) {
 366                 if (offset > inode->i_sb->s_maxbytes)
 367                         goto out_err;
 368         } else if (offset > ext4_get_htree_eof(file))
 369                 goto out_err;
 370
 371         /* Special lock needed here? */
 372         if (offset != file->f_pos) {
 373                 file->f_pos = offset;
 374                 file->f_version = 0;
 375         }
 376
 377 out_ok:
 378         ret = offset;
 379 out_err:
 380         mutex_unlock(&inode->i_mutex);
 381
 382         return ret;
 383 }
 384
 385 /*
 386  * This structure holds the nodes of the red-black tree used to store
 387  * the directory entry in hash order.
 388  */
 389 struct fname {
 390         __u32           hash;
 391         __u32           minor_hash;
 392         struct rb_node  rb_hash;
 393         struct fname    *next;
 394         __u32           inode;
 395         __u8            name_len;
 396         __u8            file_type;
 397         char            name[0];
 398 };
 399
 400 /*
 401  * This functoin implements a non-recursive way of freeing all of the
 402  * nodes in the red-black tree.
 403  */
 404 static void free_rb_tree_fname(struct rb_root *root)
 405 {
 406         struct rb_node  *n = root->rb_node;
 407         struct rb_node  *parent;
 408         struct fname    *fname;
 409
 410         while (n) {
 411                 /* Do the node's children first */
 412                 if (n->rb_left) {
 413                         n = n->rb_left;
 414                         continue;
 415                 }
 416                 if (n->rb_right) {
 417                         n = n->rb_right;
 418                         continue;
 419                 }
 420                 /*
 421                  * The node has no children; free it, and then zero
 422                  * out parent's link to it.  Finally go to the
 423                  * beginning of the loop and try to free the parent
 424                  * node.
 425                  */
 426                 parent = rb_parent(n);
 427                 fname = rb_entry(n, struct fname, rb_hash);
 428                 while (fname) {
 429                         struct fname *old = fname;
 430                         fname = fname->next;
 431                         kfree(old);
 432                 }
 433                 if (!parent)
 434                         *root = RB_ROOT;
 435                 else if (parent->rb_left == n)
 436                         parent->rb_left = NULL;
 437                 else if (parent->rb_right == n)
 438                         parent->rb_right = NULL;
 439                 n = parent;
 440         }
 441 }
 442
 443
 444 static struct dir_private_info *ext4_htree_create_dir_info(struct file *filp,
 445                                                            loff_t pos)
 446 {
 447         struct dir_private_info *p;
 448
 449         p = kzalloc(sizeof(struct dir_private_info), GFP_KERNEL);
 450         if (!p)
 451                 return NULL;
 452         p->curr_hash = pos2maj_hash(filp, pos);
 453         p->curr_minor_hash = pos2min_hash(filp, pos);
 454         return p;
 455 }
 456
 457 void ext4_htree_free_dir_info(struct dir_private_info *p)
 458 {
 459         free_rb_tree_fname(&p->root);
 460         kfree(p);
 461 }
 462
 463 /*
 464  * Given a directory entry, enter it into the fname rb tree.
 465  */
 466 int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
 467                              __u32 minor_hash,
 468                              struct ext4_dir_entry_2 *dirent)
 469 {
 470         struct rb_node **p, *parent = NULL;
 471         struct fname *fname, *new_fn;
 472         struct dir_private_info *info;
 473         int len;
 474
 475         info = dir_file->private_data;
 476         p = &info->root.rb_node;
 477
 478         /* Create and allocate the fname structure */
 479         len = sizeof(struct fname) + dirent->name_len + 1;
 480         new_fn = kzalloc(len, GFP_KERNEL);
 481         if (!new_fn)
 482                 return -ENOMEM;
 483         new_fn->hash = hash;
 484         new_fn->minor_hash = minor_hash;
 485         new_fn->inode = le32_to_cpu(dirent->inode);
 486         new_fn->name_len = dirent->name_len;
 487         new_fn->file_type = dirent->file_type;
 488         memcpy(new_fn->name, dirent->name, dirent->name_len);
 489         new_fn->name[dirent->name_len] = 0;
 490
 491         while (*p) {
 492                 parent = *p;
 493                 fname = rb_entry(parent, struct fname, rb_hash);
 494
 495                 /*
 496                  * If the hash and minor hash match up, then we put
 497                  * them on a linked list.  This rarely happens...
 498                  */
 499                 if ((new_fn->hash == fname->hash) &&
 500                     (new_fn->minor_hash == fname->minor_hash)) {
 501                         new_fn->next = fname->next;
 502                         fname->next = new_fn;
 503                         return 0;
 504                 }
 505
 506                 if (new_fn->hash < fname->hash)
 507                         p = &(*p)->rb_left;
 508                 else if (new_fn->hash > fname->hash)
 509                         p = &(*p)->rb_right;
 510                 else if (new_fn->minor_hash < fname->minor_hash)
 511                         p = &(*p)->rb_left;
 512                 else /* if (new_fn->minor_hash > fname->minor_hash) */
 513                         p = &(*p)->rb_right;
 514         }
 515
 516         rb_link_node(&new_fn->rb_hash, parent, p);
 517         rb_insert_color(&new_fn->rb_hash, &info->root);
 518         return 0;
 519 }
 520
 521
 522
 523 /*
 524  * This is a helper function for ext4_dx_readdir.  It calls filldir
 525  * for all entres on the fname linked list.  (Normally there is only
 526  * one entry on the linked list, unless there are 62 bit hash collisions.)
 527  */
 528 static int call_filldir(struct file *filp, void *dirent,
 529                         filldir_t filldir, struct fname *fname)
 530 {
 531         struct dir_private_info *info = filp->private_data;
 532         loff_t  curr_pos;
 533         struct inode *inode = filp->f_path.dentry->d_inode;
 534         struct super_block *sb;
 535         int error;
 536
 537         sb = inode->i_sb;
 538
 539         if (!fname) {
 540                 printk(KERN_ERR "EXT4-fs: call_filldir: called with "
 541                        "null fname?!?\n");
 542                 return 0;
 543         }
 544         curr_pos = hash2pos(filp, fname->hash, fname->minor_hash);
 545         while (fname) {
 546                 error = filldir(dirent, fname->name,
 547                                 fname->name_len, curr_pos,
 548                                 fname->inode,
 549                                 get_dtype(sb, fname->file_type));
 550                 if (error) {
 551                         filp->f_pos = curr_pos;
 552                         info->extra_fname = fname;
 553                         return error;
 554                 }
 555                 fname = fname->next;
 556         }
 557         return 0;
 558 }
 559
 560 static int ext4_dx_readdir(struct file *filp,
 561                          void *dirent, filldir_t filldir)
 562 {
 563         struct dir_private_info *info = filp->private_data;
 564         struct inode *inode = filp->f_path.dentry->d_inode;
 565         struct fname *fname;
 566         int     ret;
 567
 568         if (!info) {
 569                 info = ext4_htree_create_dir_info(filp, filp->f_pos);
 570                 if (!info)
 571                         return -ENOMEM;
 572                 filp->private_data = info;
 573         }
 574
 575         if (filp->f_pos == ext4_get_htree_eof(filp))
 576                 return 0;       /* EOF */
 577
 578         /* Some one has messed with f_pos; reset the world */
 579         if (info->last_pos != filp->f_pos) {
 580                 free_rb_tree_fname(&info->root);
 581                 info->curr_node = NULL;
 582                 info->extra_fname = NULL;
 583                 info->curr_hash = pos2maj_hash(filp, filp->f_pos);
 584                 info->curr_minor_hash = pos2min_hash(filp, filp->f_pos);
 585         }
 586
 587         /*
 588          * If there are any leftover names on the hash collision
 589          * chain, return them first.
 590          */
 591         if (info->extra_fname) {
 592                 if (call_filldir(filp, dirent, filldir, info->extra_fname))
 593                         goto finished;
 594                 info->extra_fname = NULL;
 595                 goto next_node;
 596         } else if (!info->curr_node)
 597                 info->curr_node = rb_first(&info->root);
 598
 599         while (1) {
 600                 /*
 601                  * Fill the rbtree if we have no more entries,
 602                  * or the inode has changed since we last read in the
 603                  * cached entries.
 604                  */
 605                 if ((!info->curr_node) ||
 606                     (filp->f_version != inode->i_version)) {
 607                         info->curr_node = NULL;
 608                         free_rb_tree_fname(&info->root);
 609                         filp->f_version = inode->i_version;
 610                         ret = ext4_htree_fill_tree(filp, info->curr_hash,
 611                                                    info->curr_minor_hash,
 612                                                    &info->next_hash);
 613                         if (ret < 0)
 614                                 return ret;
 615                         if (ret == 0) {
 616                                 filp->f_pos = ext4_get_htree_eof(filp);
 617                                 break;
 618                         }
 619                         info->curr_node = rb_first(&info->root);
 620                 }
 621
 622                 fname = rb_entry(info->curr_node, struct fname, rb_hash);
 623                 info->curr_hash = fname->hash;
 624                 info->curr_minor_hash = fname->minor_hash;
 625                 if (call_filldir(filp, dirent, filldir, fname))
 626                         break;
 627         next_node:
 628                 info->curr_node = rb_next(info->curr_node);
 629                 if (info->curr_node) {
 630                         fname = rb_entry(info->curr_node, struct fname,
 631                                          rb_hash);
 632                         info->curr_hash = fname->hash;
 633                         info->curr_minor_hash = fname->minor_hash;
 634                 } else {
 635                         if (info->next_hash == ~0) {
 636                                 filp->f_pos = ext4_get_htree_eof(filp);
 637                                 break;
 638                         }
 639                         info->curr_hash = info->next_hash;
 640                         info->curr_minor_hash = 0;
 641                 }
 642         }
 643 finished:
 644         info->last_pos = filp->f_pos;
 645         return 0;
 646 }
 647
 648 static int ext4_release_dir(struct inode *inode, struct file *filp)
 649 {
 650         if (filp->private_data)
 651                 ext4_htree_free_dir_info(filp->private_data);
 652
 653         return 0;
 654 }
 655
 656 const struct file_operations ext4_dir_operations = {
 657         .llseek         = ext4_dir_llseek,
 658         .read           = generic_read_dir,
 659         .readdir        = ext4_readdir,
 660         .unlocked_ioctl = ext4_ioctl,
 661 #ifdef CONFIG_COMPAT
 662         .compat_ioctl   = ext4_compat_ioctl,
 663 #endif
 664         .fsync          = ext4_sync_file,
 665         .release        = ext4_release_dir,
 666 };