1 /* $NetBSD: ext2fs.h,v 1.13 2003/08/07 16:34:24 agc Exp $ */ 2 3 /* 4 * Copyright (c) 1982, 1986, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * @(#)fs.h 8.10 (Berkeley) 10/27/94 32 * Modified for ext2fs by Manuel Bouyer. 33 */ 34 35 /* 36 * Copyright (c) 1997 Manuel Bouyer. 37 * 38 * Redistribution and use in source and binary forms, with or without 39 * modification, are permitted provided that the following conditions 40 * are met: 41 * 1. Redistributions of source code must retain the above copyright 42 * notice, this list of conditions and the following disclaimer. 43 * 2. Redistributions in binary form must reproduce the above copyright 44 * notice, this list of conditions and the following disclaimer in the 45 * documentation and/or other materials provided with the distribution. 46 * 3. All advertising materials mentioning features or use of this software 47 * must display the following acknowledgement: 48 * This product includes software developed by the University of 49 * California, Berkeley and its contributors. 50 * 4. Neither the name of the University nor the names of its contributors 51 * may be used to endorse or promote products derived from this software 52 * without specific prior written permission. 53 * 54 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 55 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 56 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 57 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 58 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 59 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 60 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 61 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 62 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 63 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 64 * SUCH DAMAGE. 65 * 66 * @(#)fs.h 8.10 (Berkeley) 10/27/94 67 * Modified for ext2fs by Manuel Bouyer. 68 */ 69 70 #ifndef _UFS_EXT2FS_EXT2FS_H_ 71 #define _UFS_EXT2FS_EXT2FS_H_ 72 73 #include <machine/bswap.h> 74 75 /* 76 * Each disk drive contains some number of file systems. 77 * A file system consists of a number of cylinder groups. 78 * Each cylinder group has inodes and data. 79 * 80 * A file system is described by its super-block, which in turn 81 * describes the cylinder groups. The super-block is critical 82 * data and is replicated in each cylinder group to protect against 83 * catastrophic loss. This is done at `newfs' time and the critical 84 * super-block data does not change, so the copies need not be 85 * referenced further unless disaster strikes. 86 * 87 * The first boot and super blocks are given in absolute disk addresses. 88 * The byte-offset forms are preferred, as they don't imply a sector size. 89 */ 90 #define BBSIZE 1024 91 #define SBSIZE 1024 92 #define BBOFF ((off_t)(0)) 93 #define SBOFF ((off_t)(BBOFF + BBSIZE)) 94 #define BBLOCK ((daddr_t)(0)) 95 #define SBLOCK ((daddr_t)(BBLOCK + BBSIZE / DEV_BSIZE)) 96 97 /* 98 * Addresses stored in inodes are capable of addressing blocks 99 * XXX 100 */ 101 102 /* 103 * MINBSIZE is the smallest allowable block size. 104 * MINBSIZE must be big enough to hold a cylinder group block, 105 * thus changes to (struct cg) must keep its size within MINBSIZE. 106 * Note that super blocks are always of size SBSIZE, 107 * and that both SBSIZE and MAXBSIZE must be >= MINBSIZE. 108 */ 109 #define LOG_MINBSIZE 10 110 #define MINBSIZE (1 << LOG_MINBSIZE) 111 112 /* 113 * The path name on which the file system is mounted is maintained 114 * in fs_fsmnt. MAXMNTLEN defines the amount of space allocated in 115 * the super block for this name. 116 */ 117 #define MAXMNTLEN 512 118 119 /* 120 * MINFREE gives the minimum acceptable percentage of file system 121 * blocks which may be free. If the freelist drops below this level 122 * only the superuser may continue to allocate blocks. This may 123 * be set to 0 if no reserve of free blocks is deemed necessary, 124 * however throughput drops by fifty percent if the file system 125 * is run at between 95% and 100% full; thus the minimum default 126 * value of fs_minfree is 5%. However, to get good clustering 127 * performance, 10% is a better choice. hence we use 10% as our 128 * default value. With 10% free space, fragmentation is not a 129 * problem, so we choose to optimize for time. 130 */ 131 #define MINFREE 5 132 133 /* 134 * Super block for an ext2fs file system. 135 */ 136 struct ext2fs { 137 u_int32_t e2fs_icount; /* Inode count */ 138 u_int32_t e2fs_bcount; /* blocks count */ 139 u_int32_t e2fs_rbcount; /* reserved blocks count */ 140 u_int32_t e2fs_fbcount; /* free blocks count */ 141 u_int32_t e2fs_ficount; /* free inodes count */ 142 u_int32_t e2fs_first_dblock; /* first data block */ 143 u_int32_t e2fs_log_bsize; /* block size = 1024*(2^e2fs_log_bsize) */ 144 u_int32_t e2fs_fsize; /* fragment size */ 145 u_int32_t e2fs_bpg; /* blocks per group */ 146 u_int32_t e2fs_fpg; /* frags per group */ 147 u_int32_t e2fs_ipg; /* inodes per group */ 148 u_int32_t e2fs_mtime; /* mount time */ 149 u_int32_t e2fs_wtime; /* write time */ 150 u_int16_t e2fs_mnt_count; /* mount count */ 151 u_int16_t e2fs_max_mnt_count; /* max mount count */ 152 u_int16_t e2fs_magic; /* magic number */ 153 u_int16_t e2fs_state; /* file system state */ 154 u_int16_t e2fs_beh; /* behavior on errors */ 155 u_int16_t e2fs_minrev; /* minor revision level */ 156 u_int32_t e2fs_lastfsck; /* time of last fsck */ 157 u_int32_t e2fs_fsckintv; /* max time between fscks */ 158 u_int32_t e2fs_creator; /* creator OS */ 159 u_int32_t e2fs_rev; /* revision level */ 160 u_int16_t e2fs_ruid; /* default uid for reserved blocks */ 161 u_int16_t e2fs_rgid; /* default gid for reserved blocks */ 162 /* EXT2_DYNAMIC_REV superblocks */ 163 u_int32_t e2fs_first_ino; /* first non-reserved inode */ 164 u_int16_t e2fs_inode_size; /* size of inode structure */ 165 u_int16_t e2fs_block_group_nr; /* block grp number of this sblk*/ 166 u_int32_t e2fs_features_compat; /* compatible feature set */ 167 u_int32_t e2fs_features_incompat; /* incompatible feature set */ 168 u_int32_t e2fs_features_rocompat; /* RO-compatible feature set */ 169 u_int8_t e2fs_uuid[16]; /* 128-bit uuid for volume */ 170 char e2fs_vname[16]; /* volume name */ 171 char e2fs_fsmnt[64]; /* name mounted on */ 172 u_int32_t e2fs_algo; /* For compression */ 173 u_int8_t e2fs_prealloc; /* # of blocks to preallocate */ 174 u_int8_t e2fs_dir_prealloc; /* # of blocks to preallocate for dir */ 175 u_int16_t pad1; 176 u_int32_t reserved2[204]; 177 }; 178 179 180 /* in-memory data for ext2fs */ 181 struct m_ext2fs { 182 struct ext2fs e2fs; 183 u_char e2fs_fsmnt[MAXMNTLEN]; /* name mounted on */ 184 int8_t e2fs_ronly; /* mounted read-only flag */ 185 int8_t e2fs_fmod; /* super block modified flag */ 186 int32_t e2fs_bsize; /* block size */ 187 int32_t e2fs_bshift; /* ``lblkno'' calc of logical blkno */ 188 int32_t e2fs_bmask; /* ``blkoff'' calc of blk offsets */ 189 int64_t e2fs_qbmask; /* ~fs_bmask - for use with quad size */ 190 int32_t e2fs_fsbtodb; /* fsbtodb and dbtofsb shift constant */ 191 int32_t e2fs_ncg; /* number of cylinder groups */ 192 int32_t e2fs_ngdb; /* number of group descriptor block */ 193 int32_t e2fs_ipb; /* number of inodes per block */ 194 int32_t e2fs_itpg; /* number of inode table per group */ 195 struct ext2_gd *e2fs_gd; /* group descripors */ 196 }; 197 198 199 200 /* 201 * Filesystem identification 202 */ 203 #define E2FS_MAGIC 0xef53 /* the ext2fs magic number */ 204 #define E2FS_REV0 0 /* revision levels */ 205 #define E2FS_REV1 1 /* revision levels */ 206 207 /* compatible/imcompatible features */ 208 #define EXT2F_COMPAT_PREALLOC 0x0001 209 210 #define EXT2F_ROCOMPAT_SPARSESUPER 0x0001 211 #define EXT2F_ROCOMPAT_LARGEFILE 0x0002 212 #define EXT2F_ROCOMPAT_BTREE_DIR 0x0004 213 214 #define EXT2F_INCOMPAT_COMP 0x0001 215 #define EXT2F_INCOMPAT_FTYPE 0x0002 216 217 /* features supported in this implementation */ 218 #define EXT2F_COMPAT_SUPP 0x0000 219 #define EXT2F_ROCOMPAT_SUPP EXT2F_ROCOMPAT_SPARSESUPER 220 #define EXT2F_INCOMPAT_SUPP EXT2F_INCOMPAT_FTYPE 221 222 /* 223 * OS identification 224 */ 225 #define E2FS_OS_LINUX 0 226 #define E2FS_OS_HURD 1 227 #define E2FS_OS_MASIX 2 228 229 /* 230 * Filesystem clean flags 231 */ 232 #define E2FS_ISCLEAN 0x01 233 #define E2FS_ERRORS 0x02 234 235 /* ext2 file system block group descriptor */ 236 237 struct ext2_gd { 238 u_int32_t ext2bgd_b_bitmap; /* blocks bitmap block */ 239 u_int32_t ext2bgd_i_bitmap; /* inodes bitmap block */ 240 u_int32_t ext2bgd_i_tables; /* inodes table block */ 241 u_int16_t ext2bgd_nbfree; /* number of free blocks */ 242 u_int16_t ext2bgd_nifree; /* number of free inodes */ 243 u_int16_t ext2bgd_ndirs; /* number of directories */ 244 u_int16_t reserved; 245 u_int32_t reserved2[3]; 246 247 }; 248 249 250 /* 251 * If the EXT2F_ROCOMPAT_SPARSESUPER flag is set, the cylinder group has a 252 * copy of the super and cylinder group descriptors blocks only if it's 253 * a power of 3, 5 or 7 254 */ 255 256 static __inline__ int cg_has_sb __P((int)) __attribute__((__unused__)); 257 static __inline int 258 cg_has_sb(i) 259 int i; 260 { 261 int a3 ,a5 , a7; 262 263 if (i == 0 || i == 1) 264 return 1; 265 for (a3 = 3, a5 = 5, a7 = 7; 266 a3 <= i || a5 <= i || a7 <= i; 267 a3 *= 3, a5 *= 5, a7 *= 7) 268 if (i == a3 || i == a5 || i == a7) 269 return 1; 270 return 0; 271 } 272 273 /* EXT2FS metadatas are stored in little-endian byte order. These macros 274 * helps reading theses metadatas 275 */ 276 277 #if BYTE_ORDER == LITTLE_ENDIAN 278 # define h2fs16(x) (x) 279 # define h2fs32(x) (x) 280 # define h2fs64(x) (x) 281 # define fs2h16(x) (x) 282 # define fs2h32(x) (x) 283 # define fs2h64(x) (x) 284 # define e2fs_sbload(old, new) memcpy((new), (old), SBSIZE); 285 # define e2fs_cgload(old, new, size) memcpy((new), (old), (size)); 286 # define e2fs_sbsave(old, new) memcpy((new), (old), SBSIZE); 287 # define e2fs_cgsave(old, new, size) memcpy((new), (old), (size)); 288 #else 289 void e2fs_sb_bswap __P((struct ext2fs *, struct ext2fs *)); 290 void e2fs_cg_bswap __P((struct ext2_gd *, struct ext2_gd *, int)); 291 # define h2fs16(x) bswap16(x) 292 # define h2fs32(x) bswap32(x) 293 # define h2fs64(x) bswap64(x) 294 # define fs2h16(x) bswap16(x) 295 # define fs2h32(x) bswap32(x) 296 # define fs2h64(x) bswap64(x) 297 # define e2fs_sbload(old, new) e2fs_sb_bswap((old), (new)) 298 # define e2fs_cgload(old, new, size) e2fs_cg_bswap((old), (new), (size)); 299 # define e2fs_sbsave(old, new) e2fs_sb_bswap((old), (new)) 300 # define e2fs_cgsave(old, new, size) e2fs_cg_bswap((old), (new), (size)); 301 #endif 302 303 /* 304 * Turn file system block numbers into disk block addresses. 305 * This maps file system blocks to device size blocks. 306 */ 307 #define fsbtodb(fs, b) ((b) << (fs)->e2fs_fsbtodb) 308 #define dbtofsb(fs, b) ((b) >> (fs)->e2fs_fsbtodb) 309 310 /* 311 * Macros for handling inode numbers: 312 * inode number to file system block offset. 313 * inode number to cylinder group number. 314 * inode number to file system block address. 315 */ 316 #define ino_to_cg(fs, x) (((x) - 1) / (fs)->e2fs.e2fs_ipg) 317 #define ino_to_fsba(fs, x) \ 318 ((fs)->e2fs_gd[ino_to_cg(fs, x)].ext2bgd_i_tables + \ 319 (((x)-1) % (fs)->e2fs.e2fs_ipg)/(fs)->e2fs_ipb) 320 #define ino_to_fsbo(fs, x) (((x)-1) % (fs)->e2fs_ipb) 321 322 /* 323 * Give cylinder group number for a file system block. 324 * Give cylinder group block number for a file system block. 325 */ 326 #define dtog(fs, d) (((d) - (fs)->e2fs.e2fs_first_dblock) / (fs)->e2fs.e2fs_fpg) 327 #define dtogd(fs, d) \ 328 (((d) - (fs)->e2fs.e2fs_first_dblock) % (fs)->e2fs.e2fs_fpg) 329 330 /* 331 * The following macros optimize certain frequently calculated 332 * quantities by using shifts and masks in place of divisions 333 * modulos and multiplications. 334 */ 335 #define blkoff(fs, loc) /* calculates (loc % fs->e2fs_bsize) */ \ 336 ((loc) & (fs)->e2fs_qbmask) 337 #define lblktosize(fs, blk) /* calculates (blk * fs->e2fs_bsize) */ \ 338 ((blk) << (fs)->e2fs_bshift) 339 #define lblkno(fs, loc) /* calculates (loc / fs->e2fs_bsize) */ \ 340 ((loc) >> (fs)->e2fs_bshift) 341 #define blkroundup(fs, size) /* calculates roundup(size, fs->e2fs_bsize) */ \ 342 (((size) + (fs)->e2fs_qbmask) & (fs)->e2fs_bmask) 343 #define fragroundup(fs, size) /* calculates roundup(size, fs->e2fs_bsize) */ \ 344 (((size) + (fs)->e2fs_qbmask) & (fs)->e2fs_bmask) 345 /* 346 * Determine the number of available frags given a 347 * percentage to hold in reserve. 348 */ 349 #define freespace(fs) \ 350 ((fs)->e2fs.e2fs_fbcount - (fs)->e2fs.e2fs_rbcount) 351 352 /* 353 * Number of indirects in a file system block. 354 */ 355 #define NINDIR(fs) ((fs)->e2fs_bsize / sizeof(u_int32_t)) 356 357 #endif /* !_UFS_EXT2FS_EXT2FS_H_ */ 358