2 * Copyright (c) 1982, 1986 Regents of the University of California.
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3 * All rights reserved.
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5 * Redistribution and use in source and binary forms, with or without
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6 * modification, are permitted provided that the following conditions
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8 * 1. Redistributions of source code must retain the above copyright
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9 * notice, this list of conditions and the following disclaimer.
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10 * 2. Redistributions in binary form must reproduce the above copyright
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11 * notice, this list of conditions and the following disclaimer in the
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12 * documentation and/or other materials provided with the distribution.
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13 * 3. All advertising materials mentioning features or use of this software
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14 * must display the following acknowledgement:
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15 * This product includes software developed by the University of
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16 * California, Berkeley and its contributors.
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17 * 4. Neither the name of the University nor the names of its contributors
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18 * may be used to endorse or promote products derived from this software
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19 * without specific prior written permission.
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21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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33 * from: @(#)fs.h 7.12 (Berkeley) 5/8/91
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34 * $FreeBSD: src/sys/i386/boot/dosboot/fs.h,v 1.6 1999/12/29 04:32:50 peter Exp $
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38 #define _UFS_FS_H_ 1
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43 * Each disk drive contains some number of file systems.
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44 * A file system consists of a number of cylinder groups.
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45 * Each cylinder group has inodes and data.
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47 * A file system is described by its super-block, which in turn
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48 * describes the cylinder groups. The super-block is critical
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49 * data and is replicated in each cylinder group to protect against
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50 * catastrophic loss. This is done at `newfs' time and the critical
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51 * super-block data does not change, so the copies need not be
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52 * referenced further unless disaster strikes.
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54 * For file system fs, the offsets of the various blocks of interest
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55 * are given in the super block as:
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56 * [fs->fs_sblkno] Super-block
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57 * [fs->fs_cblkno] Cylinder group block
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58 * [fs->fs_iblkno] Inode blocks
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59 * [fs->fs_dblkno] Data blocks
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60 * The beginning of cylinder group cg in fs, is given by
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61 * the ``cgbase(fs, cg)'' macro.
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63 * The first boot and super blocks are given in absolute disk addresses.
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64 * The byte-offset forms are preferred, as they don't imply a sector size.
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68 #define BBOFF ((off_t)(0))
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69 #define SBOFF ((off_t)(BBOFF + BBSIZE))
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70 #define BBLOCK ((daddr_t)(0))
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71 #define SBLOCK ((daddr_t)(BBLOCK + BBSIZE / DEV_BSIZE))
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74 * Addresses stored in inodes are capable of addressing fragments
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75 * of `blocks'. File system blocks of at most size MAXBSIZE can
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76 * be optionally broken into 2, 4, or 8 pieces, each of which is
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77 * addressible; these pieces may be DEV_BSIZE, or some multiple of
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80 * Large files consist of exclusively large data blocks. To avoid
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81 * undue wasted disk space, the last data block of a small file may be
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82 * allocated as only as many fragments of a large block as are
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83 * necessary. The file system format retains only a single pointer
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84 * to such a fragment, which is a piece of a single large block that
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85 * has been divided. The size of such a fragment is determinable from
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86 * information in the inode, using the ``blksize(fs, ip, lbn)'' macro.
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88 * The file system records space availability at the fragment level;
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89 * to determine block availability, aligned fragments are examined.
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91 * The root inode is the root of the file system.
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92 * Inode 0 can't be used for normal purposes and
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93 * historically bad blocks were linked to inode 1,
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94 * thus the root inode is 2. (inode 1 is no longer used for
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95 * this purpose, however numerous dump tapes make this
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96 * assumption, so we are stuck with it)
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98 #define ROOTINO ((ino_t)2)
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101 * MINBSIZE is the smallest allowable block size.
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102 * In order to insure that it is possible to create files of size
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103 * 2^32 with only two levels of indirection, MINBSIZE is set to 4096.
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104 * MINBSIZE must be big enough to hold a cylinder group block,
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105 * thus changes to (struct cg) must keep its size within MINBSIZE.
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106 * Note that super blocks are always of size SBSIZE,
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107 * and that both SBSIZE and MAXBSIZE must be >= MINBSIZE.
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109 #define MINBSIZE 4096
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112 * The path name on which the file system is mounted is maintained
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113 * in fs_fsmnt. MAXMNTLEN defines the amount of space allocated in
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114 * the super block for this name.
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115 * The limit on the amount of summary information per file system
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116 * is defined by MAXCSBUFS. It is currently parameterized for a
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117 * maximum of two million cylinders.
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119 #define MAXMNTLEN 512
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120 #define MAXCSBUFS 32
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123 * Per cylinder group information; summarized in blocks allocated
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124 * from first cylinder group data blocks. These blocks have to be
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125 * read in from fs_csaddr (size fs_cssize) in addition to the
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128 * N.B. sizeof(struct csum) must be a power of two in order for
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129 * the ``fs_cs'' macro to work (see below).
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132 long cs_ndir; /* number of directories */
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133 long cs_nbfree; /* number of free blocks */
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134 long cs_nifree; /* number of free inodes */
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135 long cs_nffree; /* number of free frags */
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139 * Super block for a file system.
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141 #define FS_MAGIC 0x011954
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142 #define FSOKAY 0x7c269d38
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145 struct fs *fs_link; /* linked list of file systems */
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146 struct fs *fs_rlink; /* used for incore super blocks */
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147 daddr_t fs_sblkno; /* addr of super-block in filesys */
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148 daddr_t fs_cblkno; /* offset of cyl-block in filesys */
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149 daddr_t fs_iblkno; /* offset of inode-blocks in filesys */
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150 daddr_t fs_dblkno; /* offset of first data after cg */
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151 long fs_cgoffset; /* cylinder group offset in cylinder */
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152 long fs_cgmask; /* used to calc mod fs_ntrak */
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153 time_t fs_time; /* last time written */
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154 long fs_size; /* number of blocks in fs */
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155 long fs_dsize; /* number of data blocks in fs */
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156 long fs_ncg; /* number of cylinder groups */
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157 long fs_bsize; /* size of basic blocks in fs */
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158 long fs_fsize; /* size of frag blocks in fs */
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159 long fs_frag; /* number of frags in a block in fs */
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160 /* these are configuration parameters */
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161 long fs_minfree; /* minimum percentage of free blocks */
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162 long fs_rotdelay; /* num of ms for optimal next block */
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163 long fs_rps; /* disk revolutions per second */
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164 /* these fields can be computed from the others */
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165 long fs_bmask; /* ``blkoff'' calc of blk offsets */
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166 long fs_fmask; /* ``fragoff'' calc of frag offsets */
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167 long fs_bshift; /* ``lblkno'' calc of logical blkno */
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168 long fs_fshift; /* ``numfrags'' calc number of frags */
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169 /* these are configuration parameters */
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170 long fs_maxcontig; /* max number of contiguous blks */
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171 long fs_maxbpg; /* max number of blks per cyl group */
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172 /* these fields can be computed from the others */
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173 long fs_fragshift; /* block to frag shift */
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174 long fs_fsbtodb; /* fsbtodb and dbtofsb shift constant */
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175 long fs_sbsize; /* actual size of super block */
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176 long fs_csmask; /* csum block offset */
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177 long fs_csshift; /* csum block number */
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178 long fs_nindir; /* value of NINDIR */
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179 long fs_inopb; /* value of INOPB */
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180 long fs_nspf; /* value of NSPF */
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181 /* yet another configuration parameter */
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182 long fs_optim; /* optimization preference, see below */
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183 /* these fields are derived from the hardware */
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184 long fs_npsect; /* # sectors/track including spares */
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185 long fs_interleave; /* hardware sector interleave */
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186 long fs_trackskew; /* sector 0 skew, per track */
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187 long fs_headswitch; /* head switch time, usec */
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188 long fs_trkseek; /* track-to-track seek, usec */
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189 /* sizes determined by number of cylinder groups and their sizes */
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190 daddr_t fs_csaddr; /* blk addr of cyl grp summary area */
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191 long fs_cssize; /* size of cyl grp summary area */
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192 long fs_cgsize; /* cylinder group size */
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193 /* these fields are derived from the hardware */
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194 long fs_ntrak; /* tracks per cylinder */
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195 long fs_nsect; /* sectors per track */
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196 long fs_spc; /* sectors per cylinder */
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197 /* this comes from the disk driver partitioning */
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198 long fs_ncyl; /* cylinders in file system */
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199 /* these fields can be computed from the others */
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200 long fs_cpg; /* cylinders per group */
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201 long fs_ipg; /* inodes per group */
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202 long fs_fpg; /* blocks per group * fs_frag */
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203 /* this data must be re-computed after crashes */
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204 struct csum fs_cstotal; /* cylinder summary information */
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205 /* these fields are cleared at mount time */
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206 char fs_fmod; /* super block modified flag */
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207 char fs_clean; /* file system is clean flag */
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208 char fs_ronly; /* mounted read-only flag */
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209 char fs_flags; /* currently unused flag */
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210 char fs_fsmnt[MAXMNTLEN]; /* name mounted on */
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211 /* these fields retain the current block allocation info */
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212 long fs_cgrotor; /* last cg searched */
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213 struct csum *fs_csp[MAXCSBUFS];/* list of fs_cs info buffers */
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214 long fs_cpc; /* cyl per cycle in postbl */
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215 short fs_opostbl[16][8]; /* old rotation block list head */
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216 long fs_sparecon[55]; /* reserved for future constants */
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217 long fs_state; /* validate fs_clean field */
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221 } fs_qbmask; /* ~fs_bmask - for use with quad size */
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225 } fs_qfmask; /* ~fs_fmask - for use with quad size */
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226 long fs_postblformat; /* format of positional layout tables */
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227 long fs_nrpos; /* number of rotaional positions */
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228 long fs_postbloff; /* (short) rotation block list head */
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229 long fs_rotbloff; /* (u_char) blocks for each rotation */
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230 long fs_magic; /* magic number */
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231 u_char fs_space[1]; /* list of blocks for each rotation */
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232 /* actually longer */
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235 * Preference for optimization.
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237 #define FS_OPTTIME 0 /* minimize allocation time */
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238 #define FS_OPTSPACE 1 /* minimize disk fragmentation */
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241 * Rotational layout table format types
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243 #define FS_42POSTBLFMT -1 /* 4.2BSD rotational table format */
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244 #define FS_DYNAMICPOSTBLFMT 1 /* dynamic rotational table format */
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246 * Macros for access to superblock array structures
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248 #define fs_postbl(fs, cylno) \
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249 (((fs)->fs_postblformat == FS_42POSTBLFMT) \
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250 ? ((fs)->fs_opostbl[cylno]) \
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251 : ((short *)((char *)(fs) + (fs)->fs_postbloff) + (cylno) * (fs)->fs_nrpos))
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252 #define fs_rotbl(fs) \
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253 (((fs)->fs_postblformat == FS_42POSTBLFMT) \
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254 ? ((fs)->fs_space) \
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255 : ((u_char *)((char *)(fs) + (fs)->fs_rotbloff)))
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258 * Convert cylinder group to base address of its global summary info.
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260 * N.B. This macro assumes that sizeof(struct csum) is a power of two.
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262 #define fs_cs(fs, indx) \
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263 fs_csp[(indx) >> (fs)->fs_csshift][(indx) & ~(fs)->fs_csmask]
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266 * Cylinder group block for a file system.
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268 #define CG_MAGIC 0x090255
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270 struct cg *cg_link; /* linked list of cyl groups */
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271 long cg_magic; /* magic number */
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272 time_t cg_time; /* time last written */
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273 long cg_cgx; /* we are the cgx'th cylinder group */
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274 short cg_ncyl; /* number of cyl's this cg */
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275 short cg_niblk; /* number of inode blocks this cg */
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276 long cg_ndblk; /* number of data blocks this cg */
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277 struct csum cg_cs; /* cylinder summary information */
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278 long cg_rotor; /* position of last used block */
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279 long cg_frotor; /* position of last used frag */
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280 long cg_irotor; /* position of last used inode */
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281 long cg_frsum[MAXFRAG]; /* counts of available frags */
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282 long cg_btotoff; /* (long) block totals per cylinder */
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283 long cg_boff; /* (short) free block positions */
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284 long cg_iusedoff; /* (char) used inode map */
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285 long cg_freeoff; /* (u_char) free block map */
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286 long cg_nextfreeoff; /* (u_char) next available space */
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287 long cg_sparecon[16]; /* reserved for future use */
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288 u_char cg_space[1]; /* space for cylinder group maps */
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289 /* actually longer */
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292 * Macros for access to cylinder group array structures
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294 #define cg_blktot(cgp) \
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295 (((cgp)->cg_magic != CG_MAGIC) \
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296 ? (((struct ocg *)(cgp))->cg_btot) \
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297 : ((long *)((char *)(cgp) + (cgp)->cg_btotoff)))
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298 #define cg_blks(fs, cgp, cylno) \
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299 (((cgp)->cg_magic != CG_MAGIC) \
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300 ? (((struct ocg *)(cgp))->cg_b[cylno]) \
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301 : ((short *)((char *)(cgp) + (cgp)->cg_boff) + (cylno) * (fs)->fs_nrpos))
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302 #define cg_inosused(cgp) \
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303 (((cgp)->cg_magic != CG_MAGIC) \
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304 ? (((struct ocg *)(cgp))->cg_iused) \
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305 : ((char *)((char *)(cgp) + (cgp)->cg_iusedoff)))
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306 #define cg_blksfree(cgp) \
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307 (((cgp)->cg_magic != CG_MAGIC) \
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308 ? (((struct ocg *)(cgp))->cg_free) \
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309 : ((u_char *)((char *)(cgp) + (cgp)->cg_freeoff)))
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310 #define cg_chkmagic(cgp) \
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311 ((cgp)->cg_magic == CG_MAGIC || ((struct ocg *)(cgp))->cg_magic == CG_MAGIC)
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314 * The following structure is defined
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315 * for compatibility with old file systems.
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318 struct ocg *cg_link; /* linked list of cyl groups */
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319 struct ocg *cg_rlink; /* used for incore cyl groups */
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320 time_t cg_time; /* time last written */
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321 long cg_cgx; /* we are the cgx'th cylinder group */
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322 short cg_ncyl; /* number of cyl's this cg */
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323 short cg_niblk; /* number of inode blocks this cg */
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324 long cg_ndblk; /* number of data blocks this cg */
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325 struct csum cg_cs; /* cylinder summary information */
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326 long cg_rotor; /* position of last used block */
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327 long cg_frotor; /* position of last used frag */
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328 long cg_irotor; /* position of last used inode */
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329 long cg_frsum[8]; /* counts of available frags */
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330 long cg_btot[32]; /* block totals per cylinder */
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331 short cg_b[32][8]; /* positions of free blocks */
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332 char cg_iused[256]; /* used inode map */
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333 long cg_magic; /* magic number */
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334 u_char cg_free[1]; /* free block map */
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335 /* actually longer */
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339 * Turn file system block numbers into disk block addresses.
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340 * This maps file system blocks to device size blocks.
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342 #define fsbtodb(fs, b) ((b) << (fs)->fs_fsbtodb)
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343 #define dbtofsb(fs, b) ((b) >> (fs)->fs_fsbtodb)
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346 * Cylinder group macros to locate things in cylinder groups.
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347 * They calc file system addresses of cylinder group data structures.
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349 #define cgbase(fs, c) ((daddr_t)((fs)->fs_fpg * (c)))
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350 #define cgstart(fs, c) \
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351 (cgbase(fs, c) + (fs)->fs_cgoffset * ((c) & ~((fs)->fs_cgmask)))
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352 #define cgsblock(fs, c) (cgstart(fs, c) + (fs)->fs_sblkno) /* super blk */
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353 #define cgtod(fs, c) (cgstart(fs, c) + (fs)->fs_cblkno) /* cg block */
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354 #define cgimin(fs, c) (cgstart(fs, c) + (fs)->fs_iblkno) /* inode blk */
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355 #define cgdmin(fs, c) (cgstart(fs, c) + (fs)->fs_dblkno) /* 1st data */
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358 * Macros for handling inode numbers:
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359 * inode number to file system block offset.
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360 * inode number to cylinder group number.
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361 * inode number to file system block address.
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363 #define itoo(fs, x) ((x) % INOPB(fs))
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364 #define itog(fs, x) ((x) / (fs)->fs_ipg)
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365 #define itod(fs, x) \
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366 ((daddr_t)(cgimin(fs, itog(fs, x)) + \
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367 (blkstofrags((fs), (((x) % (fs)->fs_ipg) / INOPB(fs))))))
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370 * Give cylinder group number for a file system block.
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371 * Give cylinder group block number for a file system block.
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373 #define dtog(fs, d) ((d) / (fs)->fs_fpg)
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374 #define dtogd(fs, d) ((d) % (fs)->fs_fpg)
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377 * Extract the bits for a block from a map.
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378 * Compute the cylinder and rotational position of a cyl block addr.
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380 #define blkmap(fs, map, loc) \
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381 (((map)[(loc) / NBBY] >> ((loc) % NBBY)) & (0xff >> (NBBY - (fs)->fs_frag)))
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382 #define cbtocylno(fs, bno) \
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383 ((bno) * NSPF(fs) / (fs)->fs_spc)
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384 #define cbtorpos(fs, bno) \
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385 (((bno) * NSPF(fs) % (fs)->fs_spc / (fs)->fs_nsect * (fs)->fs_trackskew + \
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386 (bno) * NSPF(fs) % (fs)->fs_spc % (fs)->fs_nsect * (fs)->fs_interleave) % \
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387 (fs)->fs_nsect * (fs)->fs_nrpos / (fs)->fs_npsect)
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390 * The following macros optimize certain frequently calculated
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391 * quantities by using shifts and masks in place of divisions
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392 * modulos and multiplications.
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394 #define blkoff(fs, loc) /* calculates (loc % fs->fs_bsize) */ \
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395 ((loc) & ~(fs)->fs_bmask)
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396 #define fragoff(fs, loc) /* calculates (loc % fs->fs_fsize) */ \
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397 ((loc) & ~(fs)->fs_fmask)
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398 #define lblktosize(fs, blk) /* calculates (blk * fs->fs_bsize) */ \
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399 ((blk) << (fs)->fs_bshift)
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400 #define lblkno(fs, loc) /* calculates (loc / fs->fs_bsize) */ \
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401 ((loc) >> (fs)->fs_bshift)
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402 #define numfrags(fs, loc) /* calculates (loc / fs->fs_fsize) */ \
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403 ((loc) >> (fs)->fs_fshift)
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404 #define blkroundup(fs, size) /* calculates roundup(size, fs->fs_bsize) */ \
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405 (((size) + (fs)->fs_bsize - 1) & (fs)->fs_bmask)
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406 #define fragroundup(fs, size) /* calculates roundup(size, fs->fs_fsize) */ \
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407 (((size) + (fs)->fs_fsize - 1) & (fs)->fs_fmask)
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408 #define fragstoblks(fs, frags) /* calculates (frags / fs->fs_frag) */ \
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409 ((frags) >> (fs)->fs_fragshift)
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410 #define blkstofrags(fs, blks) /* calculates (blks * fs->fs_frag) */ \
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411 ((blks) << (fs)->fs_fragshift)
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412 #define fragnum(fs, fsb) /* calculates (fsb % fs->fs_frag) */ \
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413 ((fsb) & ((fs)->fs_frag - 1))
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414 #define blknum(fs, fsb) /* calculates rounddown(fsb, fs->fs_frag) */ \
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415 ((fsb) &~ ((fs)->fs_frag - 1))
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418 * Determine the number of available frags given a
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419 * percentage to hold in reserve
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421 #define freespace(fs, percentreserved) \
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422 (blkstofrags((fs), (fs)->fs_cstotal.cs_nbfree) + \
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423 (fs)->fs_cstotal.cs_nffree - ((fs)->fs_dsize * (percentreserved) / 100))
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426 * Determining the size of a file block in the file system.
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428 #define blksize(fs, ip, lbn) \
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429 (((lbn) >= NDADDR || (ip)->i_size >= ((lbn) + 1) << (fs)->fs_bshift) \
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431 : (fragroundup(fs, blkoff(fs, (ip)->i_size))))
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432 #define dblksize(fs, dip, lbn) \
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433 (((lbn) >= NDADDR || (dip)->di_size >= ((lbn) + 1) << (fs)->fs_bshift) \
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435 : (fragroundup(fs, blkoff(fs, (dip)->di_size))))
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438 * Number of disk sectors per block; assumes DEV_BSIZE byte sector size.
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440 #define NSPB(fs) ((fs)->fs_nspf << (fs)->fs_fragshift)
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441 #define NSPF(fs) ((fs)->fs_nspf)
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444 * INOPB is the number of inodes in a secondary storage block.
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446 #define INOPB(fs) ((fs)->fs_inopb)
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447 #define INOPF(fs) ((fs)->fs_inopb >> (fs)->fs_fragshift)
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450 * NINDIR is the number of indirects in a file system block.
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452 #define NINDIR(fs) ((fs)->fs_nindir)
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456 extern void fserr(struct fs *, int /*uid_t*/, const char *);
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457 extern void fragacct(struct fs *, int, long *, int);
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458 extern int isblock(struct fs *, u_char *, daddr_t);
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459 extern void clrblock(struct fs *, u_char *, daddr_t);
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460 extern void setblock(struct fs *, u_char *, daddr_t);
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461 extern ino_t dirpref(struct fs *);
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462 extern daddr_t mapsearch(struct fs *, struct cg *, daddr_t, int);
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464 #endif /* _KERNEL */
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465 #endif /* _UFS_FS_H_ */
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projects / dragonfly.git / blob