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 */
50 struct vxfs_dirblk {
51 __fs16 d_free; /* free space in dirblock */
52 __fs16 d_nhash; /* no of hash chains */
53 __fs16 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 */
65 struct vxfs_direct {
66 __fs32 d_ino; /* inode number */
67 __fs16 d_reclen; /* record length */
68 __fs16 d_namelen; /* d_name length */
69 __fs16 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(sbi, dbp) \
91 ((sizeof(short) * fs16_to_cpu(sbi, dbp->d_nhash)) + 4)
92
93 #endif /* _VXFS_DIR_H_ */