1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * Copyright (c) 2000-2001 Christoph Hellwig.
4 */
5 #ifndef _VXFS_DIR_H_
6 #define _VXFS_DIR_H_
7
8 /*
9 * Veritas filesystem driver - directory structure.
10 *
11 * This file contains the definition of the vxfs directory format.
12 */
13
14
15 /*
16 * VxFS directory block header.
17 *
18 * This entry is the head of every filesystem block in a directory.
19 * It is used for free space management and additionally includes
20 * a hash for speeding up directory search (lookup).
21 *
22 * The hash may be empty and in fact we do not use it all in the
23 * Linux driver for now.
24 */
25 struct vxfs_dirblk {
26 __fs16 d_free; /* free space in dirblock */
27 __fs16 d_nhash; /* no of hash chains */
28 __fs16 d_hash[1]; /* hash chain */
29 };
30
31 /*
32 * VXFS_NAMELEN is the maximum length of the d_name field
33 * of an VxFS directory entry.
34 */
35 #define VXFS_NAMELEN 256
36
37 /*
38 * VxFS directory entry.
39 */
40 struct vxfs_direct {
41 __fs32 d_ino; /* inode number */
42 __fs16 d_reclen; /* record length */
43 __fs16 d_namelen; /* d_name length */
44 __fs16 d_hashnext; /* next hash entry */
45 char d_name[VXFS_NAMELEN]; /* name */
46 };
47
48 /*
49 * VXFS_DIRPAD defines the directory entry boundaries, is _must_ be
50 * a multiple of four.
51 * VXFS_NAMEMIN is the length of a directory entry with a NULL d_name.
52 * VXFS_DIRROUND is an internal macros that rounds a length to a value
53 * usable for directory sizes.
54 * VXFS_DIRLEN calculates the directory entry size for an entry with
55 * a d_name with size len.
56 */
57 #define VXFS_DIRPAD 4
58 #define VXFS_NAMEMIN offsetof(struct vxfs_direct, d_name)
59 #define VXFS_DIRROUND(len) ((VXFS_DIRPAD + (len) - 1) & ~(VXFS_DIRPAD -1))
60 #define VXFS_DIRLEN(len) (VXFS_DIRROUND(VXFS_NAMEMIN + (len)))
61
62 /*
63 * VXFS_DIRBLKOV is the overhead of a specific dirblock.
64 */
65 #define VXFS_DIRBLKOV(sbi, dbp) \
66 ((sizeof(short) * fs16_to_cpu(sbi, dbp->d_nhash)) + 4)
67
68 #endif /* _VXFS_DIR_H_ */
69
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