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 (is_dx_dir(inode)) {
 115                 err = ext4_dx_readdir(file, ctx);
 116                 if (err != ERR_BAD_DX_DIR) {
 117                         return err;
 118                 }
 119                 /*
 120                  * We don't set the inode dirty flag since it's not
 121                  * critical that it get flushed back to the disk.
 122                  */
 123                 ext4_clear_inode_flag(file_inode(file),
 124                                       EXT4_INODE_INDEX);
 125         }
 126
 127         if (ext4_has_inline_data(inode)) {
 128                 int has_inline_data = 1;
 129                 err = ext4_read_inline_dir(file, ctx,
 130                                            &has_inline_data);
 131                 if (has_inline_data)
 132                         return err;
 133         }
 134
 135         if (ext4_encrypted_inode(inode)) {
 136                 err = ext4_fname_crypto_alloc_buffer(inode, EXT4_NAME_LEN,
 137                                                      &fname_crypto_str);
 138                 if (err < 0)
 139                         return err;
 140         }
 141
 142         offset = ctx->pos & (sb->s_blocksize - 1);
 143
 144         while (ctx->pos < inode->i_size) {
 145                 struct ext4_map_blocks map;
 146
 147                 map.m_lblk = ctx->pos >> EXT4_BLOCK_SIZE_BITS(sb);
 148                 map.m_len = 1;
 149                 err = ext4_map_blocks(NULL, inode, &map, 0);
 150                 if (err > 0) {
 151                         pgoff_t index = map.m_pblk >>
 152                                         (PAGE_CACHE_SHIFT - inode->i_blkbits);
 153                         if (!ra_has_index(&file->f_ra, index))
 154                                 page_cache_sync_readahead(
 155                                         sb->s_bdev->bd_inode->i_mapping,
 156                                         &file->f_ra, file,
 157                                         index, 1);
 158                         file->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT;
 159                         bh = ext4_bread(NULL, inode, map.m_lblk, 0);
 160                         if (IS_ERR(bh))
 161                                 return PTR_ERR(bh);
 162                 }
 163
 164                 if (!bh) {
 165                         if (!dir_has_error) {
 166                                 EXT4_ERROR_FILE(file, 0,
 167                                                 "directory contains a "
 168                                                 "hole at offset %llu",
 169                                            (unsigned long long) ctx->pos);
 170                                 dir_has_error = 1;
 171                         }
 172                         /* corrupt size?  Maybe no more blocks to read */
 173                         if (ctx->pos > inode->i_blocks << 9)
 174                                 break;
 175                         ctx->pos += sb->s_blocksize - offset;
 176                         continue;
 177                 }
 178
 179                 /* Check the checksum */
 180                 if (!buffer_verified(bh) &&
 181                     !ext4_dirent_csum_verify(inode,
 182                                 (struct ext4_dir_entry *)bh->b_data)) {
 183                         EXT4_ERROR_FILE(file, 0, "directory fails checksum "
 184                                         "at offset %llu",
 185                                         (unsigned long long)ctx->pos);
 186                         ctx->pos += sb->s_blocksize - offset;
 187                         brelse(bh);
 188                         bh = NULL;
 189                         continue;
 190                 }
 191                 set_buffer_verified(bh);
 192
 193                 /* If the dir block has changed since the last call to
 194                  * readdir(2), then we might be pointing to an invalid
 195                  * dirent right now.  Scan from the start of the block
 196                  * to make sure. */
 197                 if (file->f_version != inode->i_version) {
 198                         for (i = 0; i < sb->s_blocksize && i < offset; ) {
 199                                 de = (struct ext4_dir_entry_2 *)
 200                                         (bh->b_data + i);
 201                                 /* It's too expensive to do a full
 202                                  * dirent test each time round this
 203                                  * loop, but we do have to test at
 204                                  * least that it is non-zero.  A
 205                                  * failure will be detected in the
 206                                  * dirent test below. */
 207                                 if (ext4_rec_len_from_disk(de->rec_len,
 208                                         sb->s_blocksize) < EXT4_DIR_REC_LEN(1))
 209                                         break;
 210                                 i += ext4_rec_len_from_disk(de->rec_len,
 211                                                             sb->s_blocksize);
 212                         }
 213                         offset = i;
 214                         ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1))
 215                                 | offset;
 216                         file->f_version = inode->i_version;
 217                 }
 218
 219                 while (ctx->pos < inode->i_size
 220                        && offset < sb->s_blocksize) {
 221                         de = (struct ext4_dir_entry_2 *) (bh->b_data + offset);
 222                         if (ext4_check_dir_entry(inode, file, de, bh,
 223                                                  bh->b_data, bh->b_size,
 224                                                  offset)) {
 225                                 /*
 226                                  * On error, skip to the next block
 227                                  */
 228                                 ctx->pos = (ctx->pos |
 229                                                 (sb->s_blocksize - 1)) + 1;
 230                                 break;
 231                         }
 232                         offset += ext4_rec_len_from_disk(de->rec_len,
 233                                         sb->s_blocksize);
 234                         if (le32_to_cpu(de->inode)) {
 235                                 if (!ext4_encrypted_inode(inode)) {
 236                                         if (!dir_emit(ctx, de->name,
 237                                             de->name_len,
 238                                             le32_to_cpu(de->inode),
 239                                             get_dtype(sb, de->file_type)))
 240                                                 goto done;
 241                                 } else {
 242                                         int save_len = fname_crypto_str.len;
 243
 244                                         /* Directory is encrypted */
 245                                         err = ext4_fname_disk_to_usr(inode,
 246                                                 NULL, de, &fname_crypto_str);
 247                                         fname_crypto_str.len = save_len;
 248                                         if (err < 0)
 249                                                 goto errout;
 250                                         if (!dir_emit(ctx,
 251                                             fname_crypto_str.name, err,
 252                                             le32_to_cpu(de->inode),
 253                                             get_dtype(sb, de->file_type)))
 254                                                 goto done;
 255                                 }
 256                         }
 257                         ctx->pos += ext4_rec_len_from_disk(de->rec_len,
 258                                                 sb->s_blocksize);
 259                 }
 260                 if ((ctx->pos < inode->i_size) && !dir_relax(inode))
 261                         goto done;
 262                 brelse(bh);
 263                 bh = NULL;
 264                 offset = 0;
 265         }
 266 done:
 267         err = 0;
 268 errout:
 269 #ifdef CONFIG_EXT4_FS_ENCRYPTION
 270         ext4_fname_crypto_free_buffer(&fname_crypto_str);
 271 #endif
 272         brelse(bh);
 273         return err;
 274 }
 275
 276 static inline int is_32bit_api(void)
 277 {
 278 #ifdef CONFIG_COMPAT
 279         return is_compat_task();
 280 #else
 281         return (BITS_PER_LONG == 32);
 282 #endif
 283 }
 284
 285 /*
 286  * These functions convert from the major/minor hash to an f_pos
 287  * value for dx directories
 288  *
 289  * Upper layer (for example NFS) should specify FMODE_32BITHASH or
 290  * FMODE_64BITHASH explicitly. On the other hand, we allow ext4 to be mounted
 291  * directly on both 32-bit and 64-bit nodes, under such case, neither
 292  * FMODE_32BITHASH nor FMODE_64BITHASH is specified.
 293  */
 294 static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor)
 295 {
 296         if ((filp->f_mode & FMODE_32BITHASH) ||
 297             (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
 298                 return major >> 1;
 299         else
 300                 return ((__u64)(major >> 1) << 32) | (__u64)minor;
 301 }
 302
 303 static inline __u32 pos2maj_hash(struct file *filp, loff_t pos)
 304 {
 305         if ((filp->f_mode & FMODE_32BITHASH) ||
 306             (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
 307                 return (pos << 1) & 0xffffffff;
 308         else
 309                 return ((pos >> 32) << 1) & 0xffffffff;
 310 }
 311
 312 static inline __u32 pos2min_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 0;
 317         else
 318                 return pos & 0xffffffff;
 319 }
 320
 321 /*
 322  * Return 32- or 64-bit end-of-file for dx directories
 323  */
 324 static inline loff_t ext4_get_htree_eof(struct file *filp)
 325 {
 326         if ((filp->f_mode & FMODE_32BITHASH) ||
 327             (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
 328                 return EXT4_HTREE_EOF_32BIT;
 329         else
 330                 return EXT4_HTREE_EOF_64BIT;
 331 }
 332
 333
 334 /*
 335  * ext4_dir_llseek() calls generic_file_llseek_size to handle htree
 336  * directories, where the "offset" is in terms of the filename hash
 337  * value instead of the byte offset.
 338  *
 339  * Because we may return a 64-bit hash that is well beyond offset limits,
 340  * we need to pass the max hash as the maximum allowable offset in
 341  * the htree directory case.
 342  *
 343  * For non-htree, ext4_llseek already chooses the proper max offset.
 344  */
 345 static loff_t ext4_dir_llseek(struct file *file, loff_t offset, int whence)
 346 {
 347         struct inode *inode = file->f_mapping->host;
 348         int dx_dir = is_dx_dir(inode);
 349         loff_t htree_max = ext4_get_htree_eof(file);
 350
 351         if (likely(dx_dir))
 352                 return generic_file_llseek_size(file, offset, whence,
 353                                                     htree_max, htree_max);
 354         else
 355                 return ext4_llseek(file, offset, whence);
 356 }
 357
 358 /*
 359  * This structure holds the nodes of the red-black tree used to store
 360  * the directory entry in hash order.
 361  */
 362 struct fname {
 363         __u32           hash;
 364         __u32           minor_hash;
 365         struct rb_node  rb_hash;
 366         struct fname    *next;
 367         __u32           inode;
 368         __u8            name_len;
 369         __u8            file_type;
 370         char            name[0];
 371 };
 372
 373 /*
 374  * This functoin implements a non-recursive way of freeing all of the
 375  * nodes in the red-black tree.
 376  */
 377 static void free_rb_tree_fname(struct rb_root *root)
 378 {
 379         struct fname *fname, *next;
 380
 381         rbtree_postorder_for_each_entry_safe(fname, next, root, rb_hash)
 382                 while (fname) {
 383                         struct fname *old = fname;
 384                         fname = fname->next;
 385                         kfree(old);
 386                 }
 387
 388         *root = RB_ROOT;
 389 }
 390
 391
 392 static struct dir_private_info *ext4_htree_create_dir_info(struct file *filp,
 393                                                            loff_t pos)
 394 {
 395         struct dir_private_info *p;
 396
 397         p = kzalloc(sizeof(struct dir_private_info), GFP_KERNEL);
 398         if (!p)
 399                 return NULL;
 400         p->curr_hash = pos2maj_hash(filp, pos);
 401         p->curr_minor_hash = pos2min_hash(filp, pos);
 402         return p;
 403 }
 404
 405 void ext4_htree_free_dir_info(struct dir_private_info *p)
 406 {
 407         free_rb_tree_fname(&p->root);
 408         kfree(p);
 409 }
 410
 411 /*
 412  * Given a directory entry, enter it into the fname rb tree.
 413  *
 414  * When filename encryption is enabled, the dirent will hold the
 415  * encrypted filename, while the htree will hold decrypted filename.
 416  * The decrypted filename is passed in via ent_name.  parameter.
 417  */
 418 int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
 419                              __u32 minor_hash,
 420                             struct ext4_dir_entry_2 *dirent,
 421                             struct ext4_str *ent_name)
 422 {
 423         struct rb_node **p, *parent = NULL;
 424         struct fname *fname, *new_fn;
 425         struct dir_private_info *info;
 426         int len;
 427
 428         info = dir_file->private_data;
 429         p = &info->root.rb_node;
 430
 431         /* Create and allocate the fname structure */
 432         len = sizeof(struct fname) + ent_name->len + 1;
 433         new_fn = kzalloc(len, GFP_KERNEL);
 434         if (!new_fn)
 435                 return -ENOMEM;
 436         new_fn->hash = hash;
 437         new_fn->minor_hash = minor_hash;
 438         new_fn->inode = le32_to_cpu(dirent->inode);
 439         new_fn->name_len = ent_name->len;
 440         new_fn->file_type = dirent->file_type;
 441         memcpy(new_fn->name, ent_name->name, ent_name->len);
 442         new_fn->name[ent_name->len] = 0;
 443
 444         while (*p) {
 445                 parent = *p;
 446                 fname = rb_entry(parent, struct fname, rb_hash);
 447
 448                 /*
 449                  * If the hash and minor hash match up, then we put
 450                  * them on a linked list.  This rarely happens...
 451                  */
 452                 if ((new_fn->hash == fname->hash) &&
 453                     (new_fn->minor_hash == fname->minor_hash)) {
 454                         new_fn->next = fname->next;
 455                         fname->next = new_fn;
 456                         return 0;
 457                 }
 458
 459                 if (new_fn->hash < fname->hash)
 460                         p = &(*p)->rb_left;
 461                 else if (new_fn->hash > fname->hash)
 462                         p = &(*p)->rb_right;
 463                 else if (new_fn->minor_hash < fname->minor_hash)
 464                         p = &(*p)->rb_left;
 465                 else /* if (new_fn->minor_hash > fname->minor_hash) */
 466                         p = &(*p)->rb_right;
 467         }
 468
 469         rb_link_node(&new_fn->rb_hash, parent, p);
 470         rb_insert_color(&new_fn->rb_hash, &info->root);
 471         return 0;
 472 }
 473
 474
 475
 476 /*
 477  * This is a helper function for ext4_dx_readdir.  It calls filldir
 478  * for all entres on the fname linked list.  (Normally there is only
 479  * one entry on the linked list, unless there are 62 bit hash collisions.)
 480  */
 481 static int call_filldir(struct file *file, struct dir_context *ctx,
 482                         struct fname *fname)
 483 {
 484         struct dir_private_info *info = file->private_data;
 485         struct inode *inode = file_inode(file);
 486         struct super_block *sb = inode->i_sb;
 487
 488         if (!fname) {
 489                 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: comm %s: "
 490                          "called with null fname?!?", __func__, __LINE__,
 491                          inode->i_ino, current->comm);
 492                 return 0;
 493         }
 494         ctx->pos = hash2pos(file, fname->hash, fname->minor_hash);
 495         while (fname) {
 496                 if (!dir_emit(ctx, fname->name,
 497                                 fname->name_len,
 498                                 fname->inode,
 499                                 get_dtype(sb, fname->file_type))) {
 500                         info->extra_fname = fname;
 501                         return 1;
 502                 }
 503                 fname = fname->next;
 504         }
 505         return 0;
 506 }
 507
 508 static int ext4_dx_readdir(struct file *file, struct dir_context *ctx)
 509 {
 510         struct dir_private_info *info = file->private_data;
 511         struct inode *inode = file_inode(file);
 512         struct fname *fname;
 513         int     ret;
 514
 515         if (!info) {
 516                 info = ext4_htree_create_dir_info(file, ctx->pos);
 517                 if (!info)
 518                         return -ENOMEM;
 519                 file->private_data = info;
 520         }
 521
 522         if (ctx->pos == ext4_get_htree_eof(file))
 523                 return 0;       /* EOF */
 524
 525         /* Some one has messed with f_pos; reset the world */
 526         if (info->last_pos != ctx->pos) {
 527                 free_rb_tree_fname(&info->root);
 528                 info->curr_node = NULL;
 529                 info->extra_fname = NULL;
 530                 info->curr_hash = pos2maj_hash(file, ctx->pos);
 531                 info->curr_minor_hash = pos2min_hash(file, ctx->pos);
 532         }
 533
 534         /*
 535          * If there are any leftover names on the hash collision
 536          * chain, return them first.
 537          */
 538         if (info->extra_fname) {
 539                 if (call_filldir(file, ctx, info->extra_fname))
 540                         goto finished;
 541                 info->extra_fname = NULL;
 542                 goto next_node;
 543         } else if (!info->curr_node)
 544                 info->curr_node = rb_first(&info->root);
 545
 546         while (1) {
 547                 /*
 548                  * Fill the rbtree if we have no more entries,
 549                  * or the inode has changed since we last read in the
 550                  * cached entries.
 551                  */
 552                 if ((!info->curr_node) ||
 553                     (file->f_version != inode->i_version)) {
 554                         info->curr_node = NULL;
 555                         free_rb_tree_fname(&info->root);
 556                         file->f_version = inode->i_version;
 557                         ret = ext4_htree_fill_tree(file, info->curr_hash,
 558                                                    info->curr_minor_hash,
 559                                                    &info->next_hash);
 560                         if (ret < 0)
 561                                 return ret;
 562                         if (ret == 0) {
 563                                 ctx->pos = ext4_get_htree_eof(file);
 564                                 break;
 565                         }
 566                         info->curr_node = rb_first(&info->root);
 567                 }
 568
 569                 fname = rb_entry(info->curr_node, struct fname, rb_hash);
 570                 info->curr_hash = fname->hash;
 571                 info->curr_minor_hash = fname->minor_hash;
 572                 if (call_filldir(file, ctx, fname))
 573                         break;
 574         next_node:
 575                 info->curr_node = rb_next(info->curr_node);
 576                 if (info->curr_node) {
 577                         fname = rb_entry(info->curr_node, struct fname,
 578                                          rb_hash);
 579                         info->curr_hash = fname->hash;
 580                         info->curr_minor_hash = fname->minor_hash;
 581                 } else {
 582                         if (info->next_hash == ~0) {
 583                                 ctx->pos = ext4_get_htree_eof(file);
 584                                 break;
 585                         }
 586                         info->curr_hash = info->next_hash;
 587                         info->curr_minor_hash = 0;
 588                 }
 589         }
 590 finished:
 591         info->last_pos = ctx->pos;
 592         return 0;
 593 }
 594
 595 static int ext4_dir_open(struct inode * inode, struct file * filp)
 596 {
 597         if (ext4_encrypted_inode(inode))
 598                 return ext4_get_encryption_info(inode) ? -EACCES : 0;
 599         return 0;
 600 }
 601
 602 static int ext4_release_dir(struct inode *inode, struct file *filp)
 603 {
 604         if (filp->private_data)
 605                 ext4_htree_free_dir_info(filp->private_data);
 606
 607         return 0;
 608 }
 609
 610 int ext4_check_all_de(struct inode *dir, struct buffer_head *bh, void *buf,
 611                       int buf_size)
 612 {
 613         struct ext4_dir_entry_2 *de;
 614         int nlen, rlen;
 615         unsigned int offset = 0;
 616         char *top;
 617
 618         de = (struct ext4_dir_entry_2 *)buf;
 619         top = buf + buf_size;
 620         while ((char *) de < top) {
 621                 if (ext4_check_dir_entry(dir, NULL, de, bh,
 622                                          buf, buf_size, offset))
 623                         return -EFSCORRUPTED;
 624                 nlen = EXT4_DIR_REC_LEN(de->name_len);
 625                 rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
 626                 de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
 627                 offset += rlen;
 628         }
 629         if ((char *) de > top)
 630                 return -EFSCORRUPTED;
 631
 632         return 0;
 633 }
 634
 635 const struct file_operations ext4_dir_operations = {
 636         .llseek         = ext4_dir_llseek,
 637         .read           = generic_read_dir,
 638         .iterate        = ext4_readdir,
 639         .unlocked_ioctl = ext4_ioctl,
 640 #ifdef CONFIG_COMPAT
 641         .compat_ioctl   = ext4_compat_ioctl,
 642 #endif
 643         .fsync          = ext4_sync_file,
 644         .open           = ext4_dir_open,
 645         .release        = ext4_release_dir,
 646 };