1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
|
/*-
* modified for EXT2FS support in Lites 1.1
*
* Aug 1995, Godmar Back (gback@cs.utah.edu)
* University of Utah, Department of Computer Science
*/
/*-
* Copyright (c) 1982, 1986, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)fs.h 8.7 (Berkeley) 4/19/94
* $FreeBSD$
*/
/*
* Each disk drive contains some number of file systems.
* A file system consists of a number of cylinder groups.
* Each cylinder group has inodes and data.
*
* A file system is described by its super-block, which in turn
* describes the cylinder groups. The super-block is critical
* data and is replicated in each cylinder group to protect against
* catastrophic loss. This is done at `newfs' time and the critical
* super-block data does not change, so the copies need not be
* referenced further unless disaster strikes.
*
* The first boot and super blocks are given in absolute disk addresses.
* The byte-offset forms are preferred, as they don't imply a sector size.
*/
#define SBSIZE 1024
#define SBLOCK 2
/*
* The path name on which the file system is mounted is maintained
* in fs_fsmnt. MAXMNTLEN defines the amount of space allocated in
* the super block for this name.
*/
#define MAXMNTLEN 512
/*
* Grigoriy Orlov <gluk@ptci.ru> has done some extensive work to fine
* tune the layout preferences for directories within a filesystem.
* His algorithm can be tuned by adjusting the following parameters
* which tell the system the average file size and the average number
* of files per directory. These defaults are well selected for typical
* filesystems, but may need to be tuned for odd cases like filesystems
* being used for squid caches or news spools.
* AVFPDIR is the expected number of files per directory. AVGDIRSIZE is
* obtained by multiplying AVFPDIR and AVFILESIZ which is assumed to be
* 16384.
*/
#define AFPDIR 64
#define AVGDIRSIZE 1048576
/*
* Macros for access to superblock array structures
*/
/*
* Turn file system block numbers into disk block addresses.
* This maps file system blocks to device size blocks.
*/
#define fsbtodb(fs, b) ((b) << ((fs)->e2fs_fsbtodb))
#define dbtofsb(fs, b) ((b) >> ((fs)->e2fs_fsbtodb))
/* get group containing inode */
#define ino_to_cg(fs, x) (((x) - 1) / (fs->e2fs_ipg))
/* get block containing inode from its number x */
#define ino_to_fsba(fs, x) \
((fs)->e2fs_gd[ino_to_cg((fs), (x))].ext2bgd_i_tables + \
(((x) - 1) % (fs)->e2fs->e2fs_ipg) / (fs)->e2fs_ipb)
/* get offset for inode in block */
#define ino_to_fsbo(fs, x) ((x-1) % (fs->e2fs_ipb))
/*
* Give cylinder group number for a file system block.
* Give cylinder group block number for a file system block.
*/
#define dtog(fs, d) (((d) - fs->e2fs->e2fs_first_dblock) / \
EXT2_BLOCKS_PER_GROUP(fs))
#define dtogd(fs, d) (((d) - fs->e2fs->e2fs_first_dblock) % \
EXT2_BLOCKS_PER_GROUP(fs))
/*
* The following macros optimize certain frequently calculated
* quantities by using shifts and masks in place of divisions
* modulos and multiplications.
*/
#define blkoff(fs, loc) /* calculates (loc % fs->fs_bsize) */ \
((loc) & (fs)->e2fs_qbmask)
#define lblktosize(fs, blk) /* calculates (blk * fs->fs_bsize) */ \
((blk) << (fs->e2fs_bshift))
#define lblkno(fs, loc) /* calculates (loc / fs->fs_bsize) */ \
((loc) >> (fs->e2fs_bshift))
/* no fragments -> logical block number equal # of frags */
#define numfrags(fs, loc) /* calculates (loc / fs->fs_fsize) */ \
((loc) >> (fs->e2fs_bshift))
#define fragroundup(fs, size) /* calculates roundup(size, fs->fs_fsize) */ \
roundup(size, fs->e2fs_fsize)
/* was (((size) + (fs)->fs_qfmask) & (fs)->fs_fmask) */
/*
* Determining the size of a file block in the file system.
* easy w/o fragments
*/
#define blksize(fs, ip, lbn) ((fs)->e2fs_fsize)
/*
* INOPB is the number of inodes in a secondary storage block.
*/
#define INOPB(fs) (fs->e2fs_ipb)
/*
* NINDIR is the number of indirects in a file system block.
*/
#define NINDIR(fs) (EXT2_ADDR_PER_BLOCK(fs))
extern int inside[], around[];
extern u_char *fragtbl[];
|
