xref: /openbmc/linux/fs/freevxfs/vxfs_dir.h (revision 0b1e987c)
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