linux/fs/freevxfs/vxfs_dir.h
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   1/*
   2 * Copyright (c) 2000-2001 Christoph Hellwig.
   3 * All rights reserved.
   4 *
   5 * Redistribution and use in source and binary forms, with or without
   6 * modification, are permitted provided that the following conditions
   7 * are met:
   8 * 1. Redistributions of source code must retain the above copyright
   9 *    notice, this list of conditions, and the following disclaimer,
  10 *    without modification.
  11 * 2. The name of the author may not be used to endorse or promote products
  12 *    derived from this software without specific prior written permission.
  13 *
  14 * Alternatively, this software may be distributed under the terms of the
  15 * GNU General Public License ("GPL").
  16 *
  17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
  21 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27 * SUCH DAMAGE.
  28 *
  29 */
  30#ifndef _VXFS_DIR_H_
  31#define _VXFS_DIR_H_
  32
  33/*
  34 * Veritas filesystem driver - directory structure.
  35 *
  36 * This file contains the definition of the vxfs directory format.
  37 */
  38
  39
  40/*
  41 * VxFS directory block header.
  42 *
  43 * This entry is the head of every filesystem block in a directory.
  44 * It is used for free space management and additionally includes
  45 * a hash for speeding up directory search (lookup).
  46 *
  47 * The hash may be empty and in fact we do not use it all in the
  48 * Linux driver for now.
  49 */
  50struct vxfs_dirblk {
  51        u_int16_t       d_free;         /* free space in dirblock */
  52        u_int16_t       d_nhash;        /* no of hash chains */
  53        u_int16_t       d_hash[1];      /* hash chain */
  54};
  55
  56/*
  57 * VXFS_NAMELEN is the maximum length of the d_name field
  58 *      of an VxFS directory entry.
  59 */
  60#define VXFS_NAMELEN    256
  61
  62/*
  63 * VxFS directory entry.
  64 */
  65struct vxfs_direct {
  66        vx_ino_t        d_ino;                  /* inode number */
  67        u_int16_t       d_reclen;               /* record length */
  68        u_int16_t       d_namelen;              /* d_name length */
  69        u_int16_t       d_hashnext;             /* next hash entry */
  70        char            d_name[VXFS_NAMELEN];   /* name */
  71};
  72
  73/*
  74 * VXFS_DIRPAD defines the directory entry boundaries, is _must_ be
  75 *      a multiple of four.
  76 * VXFS_NAMEMIN is the length of a directory entry with a NULL d_name.
  77 * VXFS_DIRROUND is an internal macros that rounds a length to a value
  78 *      usable for directory sizes.
  79 * VXFS_DIRLEN calculates the directory entry size for an entry with
  80 *      a d_name with size len.
  81 */
  82#define VXFS_DIRPAD             4
  83#define VXFS_NAMEMIN            offsetof(struct vxfs_direct, d_name)
  84#define VXFS_DIRROUND(len)      ((VXFS_DIRPAD + (len) - 1) & ~(VXFS_DIRPAD -1))
  85#define VXFS_DIRLEN(len)        (VXFS_DIRROUND(VXFS_NAMEMIN + (len)))
  86
  87/*
  88 * VXFS_DIRBLKOV is the overhead of a specific dirblock.
  89 */
  90#define VXFS_DIRBLKOV(dbp)      ((sizeof(short) * dbp->d_nhash) + 4)
  91
  92#endif /* _VXFS_DIR_H_ */
  93
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