Unconditionally initialize a VM object for a directory vnode. Continue
[dragonfly.git] / sys / vfs / gnu / 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 $
1f1db49f 41 * $DragonFly: src/sys/vfs/gnu/ext2fs/fs.h,v 1.8 2006/04/04 17:34:32 dillon Exp $
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42 */
43
44/*
45 * Each disk drive contains some number of file systems.
46 * A file system consists of a number of cylinder groups.
47 * Each cylinder group has inodes and data.
48 *
49 * A file system is described by its super-block, which in turn
50 * describes the cylinder groups. The super-block is critical
51 * data and is replicated in each cylinder group to protect against
52 * catastrophic loss. This is done at `newfs' time and the critical
53 * super-block data does not change, so the copies need not be
54 * referenced further unless disaster strikes.
55 *
56 * The first boot and super blocks are given in absolute disk addresses.
57 * The byte-offset forms are preferred, as they don't imply a sector size.
58 */
59#define BBSIZE 1024
60#define SBSIZE 1024
61#define BBOFF ((off_t)(0))
62#define SBOFF ((off_t)(BBOFF + BBSIZE))
63#define BBLOCK ((daddr_t)(0))
64#define SBLOCK ((daddr_t)(BBLOCK + BBSIZE / DEV_BSIZE))
65
66/*
67 * The path name on which the file system is mounted is maintained
68 * in fs_fsmnt. MAXMNTLEN defines the amount of space allocated in
69 * the super block for this name.
70 */
71#define MAXMNTLEN 512
72
73/*
74 * Macros for access to superblock array structures
75 */
76
77/*
78 * Convert cylinder group to base address of its global summary info.
79 */
80#define fs_cs(fs, cgindx) (((struct ext2_group_desc *) \
81 (fs->s_group_desc[cgindx / EXT2_DESC_PER_BLOCK(fs)]->b_data)) \
82 [cgindx % EXT2_DESC_PER_BLOCK(fs)])
83
84/*
85 * Turn file system block numbers into disk block addresses.
86 * This maps file system blocks to device size blocks.
87 */
88#define fsbtodb(fs, b) ((b) << ((fs)->s_fsbtodb))
89#define dbtofsb(fs, b) ((b) >> ((fs)->s_fsbtodb))
90
91/* get group containing inode */
92#define ino_to_cg(fs, x) (((x) - 1) / EXT2_INODES_PER_GROUP(fs))
93
94/* get block containing inode from its number x */
95#define ino_to_fsba(fs, x) fs_cs(fs, ino_to_cg(fs, x)).bg_inode_table + \
96 (((x)-1) % EXT2_INODES_PER_GROUP(fs))/EXT2_INODES_PER_BLOCK(fs)
97
98/* get offset for inode in block */
99#define ino_to_fsbo(fs, x) ((x-1) % EXT2_INODES_PER_BLOCK(fs))
100
101/*
102 * Give cylinder group number for a file system block.
103 * Give cylinder group block number for a file system block.
104 */
105#define dtog(fs, d) (((d) - fs->s_es->s_first_data_block) / \
106 EXT2_BLOCKS_PER_GROUP(fs))
107#define dtogd(fs, d) (((d) - fs->s_es->s_first_data_block) % \
108 EXT2_BLOCKS_PER_GROUP(fs))
109
110/*
111 * The following macros optimize certain frequently calculated
112 * quantities by using shifts and masks in place of divisions
113 * modulos and multiplications.
114 */
115#define blkoff(fs, loc) /* calculates (loc % fs->fs_bsize) */ \
116 ((loc) & (fs)->s_qbmask)
117
118#define lblktosize(fs, blk) /* calculates (blk * fs->fs_bsize) */ \
119 ((blk) << (fs->s_bshift))
120
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121/*
122 * Used when converting logical blocks to offsets for getblk, bread,
123 * etc.
124 */
125#define lblktodoff(fs, blk) /* calculates (blk * fs->fs_bsize) */ \
126 ((off_t)(blk) << (fs)->s_bshift)
127#define fsbtodoff(fs, blk) /* calculates (blk * fs->fs_fsize) */ \
128 ((off_t)(blk) * (fs)->s_frag_size)
129#define dofftofsb(fs, blk) /* calculates blk / fs->fs_fsize */ \
130 ((daddr_t)((blk) / (fs)->s_frag_size))
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131#define dbtodoff(fs, b) /* calculates diskblk * fs->fs_size */ \
132 ((off_t)(b) << ((fs)->s_bshift - (fs)->s_fsbtodb))
54078292 133
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134#define lblkno(fs, loc) /* calculates (loc / fs->fs_bsize) */ \
135 ((loc) >> (fs->s_bshift))
136
137/* no fragments -> logical block number equal # of frags */
138#define numfrags(fs, loc) /* calculates (loc / fs->fs_fsize) */ \
139 ((loc) >> (fs->s_bshift))
140
141#define fragroundup(fs, size) /* calculates roundup(size, fs->fs_fsize) */ \
142 roundup(size, fs->s_frag_size)
143 /* was (((size) + (fs)->fs_qfmask) & (fs)->fs_fmask) */
144
145/*
146 * Determining the size of a file block in the file system.
147 * easy w/o fragments
148 */
149#define blksize(fs, ip, lbn) ((fs)->s_frag_size)
150
151/*
152 * INOPB is the number of inodes in a secondary storage block.
153 */
154#define INOPB(fs) EXT2_INODES_PER_BLOCK(fs)
155
156/*
157 * NINDIR is the number of indirects in a file system block.
158 */
159#define NINDIR(fs) (EXT2_ADDR_PER_BLOCK(fs))
160
161extern int inside[], around[];
162extern u_char *fragtbl[];
163
164/* a few remarks about superblock locking/unlocking
165 * Linux provides special routines for doing so
166 * I haven't figured out yet what BSD does
167 * I think I'll try a VOP_LOCK/VOP_UNLOCK on the device vnode
168 */
1f1db49f 169#define DEVVP(inode) (VFSTOEXT2(ITOV(inode)->v_mount)->um_devvp)
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170#define lock_super(devvp) vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, curthread)
171#define unlock_super(devvp) VOP_UNLOCK(devvp, 0, curthread)
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172
173/*
174 * To lock a buffer, set the B_LOCKED flag and then brelse() it. To unlock,
175 * reset the B_LOCKED flag and brelse() the buffer back on the LRU list
176 */
177#define LCK_BUF(bp) { \
165dba55 178 crit_enter(); \
984263bc 179 (bp)->b_flags |= B_LOCKED; \
165dba55 180 crit_exit(); \
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181 brelse(bp); \
182}
183
184#define ULCK_BUF(bp) { \
185 long flags; \
165dba55 186 crit_enter(); \
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187 flags = (bp)->b_flags; \
188 (bp)->b_flags &= ~(B_DIRTY | B_LOCKED); \
189 BUF_LOCK(bp, LK_EXCLUSIVE); \
190 bremfree(bp); \
165dba55 191 crit_exit(); \
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192 if (flags & B_DIRTY) \
193 bwrite(bp); \
194 else \
195 brelse(bp); \
196}