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[dragonfly.git] / sys / vfs / gnu / ext2fs / fs.h
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MD
1/*
2 * modified for EXT2FS support in Lites 1.1
3 *
4 * Aug 1995, Godmar Back (gback@cs.utah.edu)
5 * University of Utah, Department of Computer Science
6 */
7/*
8 * Copyright (c) 1982, 1986, 1993
9 * The Regents of the University of California. All rights reserved.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 * must display the following acknowledgement:
21 * This product includes software developed by the University of
22 * California, Berkeley and its contributors.
23 * 4. Neither the name of the University nor the names of its contributors
24 * may be used to endorse or promote products derived from this software
25 * without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * SUCH DAMAGE.
38 *
39 * @(#)fs.h 8.7 (Berkeley) 4/19/94
40 * $FreeBSD: src/sys/gnu/ext2fs/fs.h,v 1.5.2.1 2000/11/11 13:12:45 bde Exp $
41 */
42
43/*
44 * Each disk drive contains some number of file systems.
45 * A file system consists of a number of cylinder groups.
46 * Each cylinder group has inodes and data.
47 *
48 * A file system is described by its super-block, which in turn
49 * describes the cylinder groups. The super-block is critical
50 * data and is replicated in each cylinder group to protect against
51 * catastrophic loss. This is done at `newfs' time and the critical
52 * super-block data does not change, so the copies need not be
53 * referenced further unless disaster strikes.
54 *
55 * The first boot and super blocks are given in absolute disk addresses.
56 * The byte-offset forms are preferred, as they don't imply a sector size.
57 */
58#define BBSIZE 1024
59#define SBSIZE 1024
60#define BBOFF ((off_t)(0))
61#define SBOFF ((off_t)(BBOFF + BBSIZE))
62#define BBLOCK ((daddr_t)(0))
63#define SBLOCK ((daddr_t)(BBLOCK + BBSIZE / DEV_BSIZE))
64
65/*
66 * The path name on which the file system is mounted is maintained
67 * in fs_fsmnt. MAXMNTLEN defines the amount of space allocated in
68 * the super block for this name.
69 */
70#define MAXMNTLEN 512
71
72/*
73 * Macros for access to superblock array structures
74 */
75
76/*
77 * Convert cylinder group to base address of its global summary info.
78 */
79#define fs_cs(fs, cgindx) (((struct ext2_group_desc *) \
80 (fs->s_group_desc[cgindx / EXT2_DESC_PER_BLOCK(fs)]->b_data)) \
81 [cgindx % EXT2_DESC_PER_BLOCK(fs)])
82
83/*
84 * Turn file system block numbers into disk block addresses.
85 * This maps file system blocks to device size blocks.
86 */
87#define fsbtodb(fs, b) ((b) << ((fs)->s_fsbtodb))
88#define dbtofsb(fs, b) ((b) >> ((fs)->s_fsbtodb))
89
90/* get group containing inode */
91#define ino_to_cg(fs, x) (((x) - 1) / EXT2_INODES_PER_GROUP(fs))
92
93/* get block containing inode from its number x */
94#define ino_to_fsba(fs, x) fs_cs(fs, ino_to_cg(fs, x)).bg_inode_table + \
95 (((x)-1) % EXT2_INODES_PER_GROUP(fs))/EXT2_INODES_PER_BLOCK(fs)
96
97/* get offset for inode in block */
98#define ino_to_fsbo(fs, x) ((x-1) % EXT2_INODES_PER_BLOCK(fs))
99
100/*
101 * Give cylinder group number for a file system block.
102 * Give cylinder group block number for a file system block.
103 */
104#define dtog(fs, d) (((d) - fs->s_es->s_first_data_block) / \
105 EXT2_BLOCKS_PER_GROUP(fs))
106#define dtogd(fs, d) (((d) - fs->s_es->s_first_data_block) % \
107 EXT2_BLOCKS_PER_GROUP(fs))
108
109/*
110 * The following macros optimize certain frequently calculated
111 * quantities by using shifts and masks in place of divisions
112 * modulos and multiplications.
113 */
114#define blkoff(fs, loc) /* calculates (loc % fs->fs_bsize) */ \
115 ((loc) & (fs)->s_qbmask)
116
117#define lblktosize(fs, blk) /* calculates (blk * fs->fs_bsize) */ \
118 ((blk) << (fs->s_bshift))
119
120#define lblkno(fs, loc) /* calculates (loc / fs->fs_bsize) */ \
121 ((loc) >> (fs->s_bshift))
122
123/* no fragments -> logical block number equal # of frags */
124#define numfrags(fs, loc) /* calculates (loc / fs->fs_fsize) */ \
125 ((loc) >> (fs->s_bshift))
126
127#define fragroundup(fs, size) /* calculates roundup(size, fs->fs_fsize) */ \
128 roundup(size, fs->s_frag_size)
129 /* was (((size) + (fs)->fs_qfmask) & (fs)->fs_fmask) */
130
131/*
132 * Determining the size of a file block in the file system.
133 * easy w/o fragments
134 */
135#define blksize(fs, ip, lbn) ((fs)->s_frag_size)
136
137/*
138 * INOPB is the number of inodes in a secondary storage block.
139 */
140#define INOPB(fs) EXT2_INODES_PER_BLOCK(fs)
141
142/*
143 * NINDIR is the number of indirects in a file system block.
144 */
145#define NINDIR(fs) (EXT2_ADDR_PER_BLOCK(fs))
146
147extern int inside[], around[];
148extern u_char *fragtbl[];
149
150/* a few remarks about superblock locking/unlocking
151 * Linux provides special routines for doing so
152 * I haven't figured out yet what BSD does
153 * I think I'll try a VOP_LOCK/VOP_UNLOCK on the device vnode
154 */
155#define DEVVP(inode) (VFSTOUFS(ITOV(inode)->v_mount)->um_devvp)
156#define lock_super(devvp) vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, curproc)
157#define unlock_super(devvp) VOP_UNLOCK(devvp, 0, curproc)
158
159/*
160 * To lock a buffer, set the B_LOCKED flag and then brelse() it. To unlock,
161 * reset the B_LOCKED flag and brelse() the buffer back on the LRU list
162 */
163#define LCK_BUF(bp) { \
164 int s; \
165 s = splbio(); \
166 (bp)->b_flags |= B_LOCKED; \
167 splx(s); \
168 brelse(bp); \
169}
170
171#define ULCK_BUF(bp) { \
172 long flags; \
173 int s; \
174 s = splbio(); \
175 flags = (bp)->b_flags; \
176 (bp)->b_flags &= ~(B_DIRTY | B_LOCKED); \
177 BUF_LOCK(bp, LK_EXCLUSIVE); \
178 bremfree(bp); \
179 splx(s); \
180 if (flags & B_DIRTY) \
181 bwrite(bp); \
182 else \
183 brelse(bp); \
184}