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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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 managment 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 ((int)((struct vxfs_direct *)0)->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_ */