kernel: Move GPL'd kernel files to sys/gnu to have them all in one place.
[dragonfly.git] / sys / gnu / vfs / ext2fs / fs.h
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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
b993bb87 67 * in fs_fsmnt. MAXMNTLEN defines the amount of space allocated in
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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 */
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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))
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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
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120/*
121 * Used when converting logical blocks to offsets for getblk, bread,
122 * etc.
123 */
124#define lblktodoff(fs, blk) /* calculates (blk * fs->fs_bsize) */ \
125 ((off_t)(blk) << (fs)->s_bshift)
126#define fsbtodoff(fs, blk) /* calculates (blk * fs->fs_fsize) */ \
127 ((off_t)(blk) * (fs)->s_frag_size)
128#define dofftofsb(fs, blk) /* calculates blk / fs->fs_fsize */ \
129 ((daddr_t)((blk) / (fs)->s_frag_size))
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130#define dbtodoff(fs, b) /* calculates diskblk * sectorsize */ \
131 ((off_t)(b) * ((fs)->s_frag_size >> (fs)->s_fsbtodb))
54078292 132
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133#define lblkno(fs, loc) /* calculates (loc / fs->fs_bsize) */ \
134 ((loc) >> (fs->s_bshift))
135
136/* no fragments -> logical block number equal # of frags */
137#define numfrags(fs, loc) /* calculates (loc / fs->fs_fsize) */ \
138 ((loc) >> (fs->s_bshift))
139
140#define fragroundup(fs, size) /* calculates roundup(size, fs->fs_fsize) */ \
141 roundup(size, fs->s_frag_size)
142 /* was (((size) + (fs)->fs_qfmask) & (fs)->fs_fmask) */
143
144/*
145 * Determining the size of a file block in the file system.
146 * easy w/o fragments
147 */
148#define blksize(fs, ip, lbn) ((fs)->s_frag_size)
149
150/*
151 * INOPB is the number of inodes in a secondary storage block.
152 */
153#define INOPB(fs) EXT2_INODES_PER_BLOCK(fs)
154
155/*
156 * NINDIR is the number of indirects in a file system block.
157 */
158#define NINDIR(fs) (EXT2_ADDR_PER_BLOCK(fs))
159
160extern int inside[], around[];
161extern u_char *fragtbl[];
162
163/* a few remarks about superblock locking/unlocking
164 * Linux provides special routines for doing so
165 * I haven't figured out yet what BSD does
a11aaa81 166 * I think I'll try a vn_lock/vn_unlock on the device vnode
984263bc 167 */
1f1db49f 168#define DEVVP(inode) (VFSTOEXT2(ITOV(inode)->v_mount)->um_devvp)
ca466bae 169#define lock_super(devvp) vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY)
a11aaa81 170#define unlock_super(devvp) vn_unlock(devvp)
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171
172/*
173 * To lock a buffer, set the B_LOCKED flag and then brelse() it. To unlock,
174 * reset the B_LOCKED flag and brelse() the buffer back on the LRU list
175 */
176#define LCK_BUF(bp) { \
165dba55 177 crit_enter(); \
984263bc 178 (bp)->b_flags |= B_LOCKED; \
165dba55 179 crit_exit(); \
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180 brelse(bp); \
181}
182
183#define ULCK_BUF(bp) { \
184 long flags; \
165dba55 185 crit_enter(); \
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186 flags = (bp)->b_flags; \
187 (bp)->b_flags &= ~(B_DIRTY | B_LOCKED); \
188 BUF_LOCK(bp, LK_EXCLUSIVE); \
189 bremfree(bp); \
165dba55 190 crit_exit(); \
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191 if (flags & B_DIRTY) \
192 bwrite(bp); \
193 else \
194 brelse(bp); \
195}