xref: /openbmc/linux/fs/freevxfs/vxfs_dir.h (revision 275876e2)
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 	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  */
65 struct 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