1 /* $NetBSD: ext2fs.h,v 1.20 2005/12/24 20:45:09 perry 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 Manuel Bouyer. 49 * 4. The name of the author may not be used to endorse or promote products 50 * derived from this software without specific prior written permission. 51 * 52 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 53 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 54 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 55 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 56 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 57 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 58 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 59 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 60 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 61 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 62 * 63 * @(#)fs.h 8.10 (Berkeley) 10/27/94 64 * Modified for ext2fs by Manuel Bouyer. 65 */ 66 67 #ifndef _UFS_EXT2FS_EXT2FS_H_ 68 #define _UFS_EXT2FS_EXT2FS_H_ 69 70 #include <machine/bswap.h> 71 72 /* 73 * Each disk drive contains some number of file systems. 74 * A file system consists of a number of cylinder groups. 75 * Each cylinder group has inodes and data. 76 * 77 * A file system is described by its super-block, which in turn 78 * describes the cylinder groups. The super-block is critical 79 * data and is replicated in each cylinder group to protect against 80 * catastrophic loss. This is done at `newfs' time and the critical 81 * super-block data does not change, so the copies need not be 82 * referenced further unless disaster strikes. 83 * 84 * The first boot and super blocks are given in absolute disk addresses. 85 * The byte-offset forms are preferred, as they don't imply a sector size. 86 */ 87 #define BBSIZE 1024 88 #define SBSIZE 1024 89 #define BBOFF ((off_t)(0)) 90 #define SBOFF ((off_t)(BBOFF + BBSIZE)) 91 #define BBLOCK ((daddr_t)(0)) 92 #define SBLOCK ((daddr_t)(BBLOCK + BBSIZE / DEV_BSIZE)) 93 94 /* 95 * Addresses stored in inodes are capable of addressing blocks 96 * XXX 97 */ 98 99 /* 100 * MINBSIZE is the smallest allowable block size. 101 * MINBSIZE must be big enough to hold a cylinder group block, 102 * thus changes to (struct cg) must keep its size within MINBSIZE. 103 * Note that super blocks are always of size SBSIZE, 104 * and that both SBSIZE and MAXBSIZE must be >= MINBSIZE. 105 */ 106 #define LOG_MINBSIZE 10 107 #define MINBSIZE (1 << LOG_MINBSIZE) 108 109 /* 110 * The path name on which the file system is mounted is maintained 111 * in fs_fsmnt. MAXMNTLEN defines the amount of space allocated in 112 * the super block for this name. 113 */ 114 #define MAXMNTLEN 512 115 116 /* 117 * MINFREE gives the minimum acceptable percentage of file system 118 * blocks which may be free. If the freelist drops below this level 119 * only the superuser may continue to allocate blocks. This may 120 * be set to 0 if no reserve of free blocks is deemed necessary, 121 * however throughput drops by fifty percent if the file system 122 * is run at between 95% and 100% full; thus the minimum default 123 * value of fs_minfree is 5%. However, to get good clustering 124 * performance, 10% is a better choice. hence we use 10% as our 125 * default value. With 10% free space, fragmentation is not a 126 * problem, so we choose to optimize for time. 127 */ 128 #define MINFREE 5 129 130 /* 131 * Super block for an ext2fs file system. 132 */ 133 struct ext2fs { 134 u_int32_t e2fs_icount; /* Inode count */ 135 u_int32_t e2fs_bcount; /* blocks count */ 136 u_int32_t e2fs_rbcount; /* reserved blocks count */ 137 u_int32_t e2fs_fbcount; /* free blocks count */ 138 u_int32_t e2fs_ficount; /* free inodes count */ 139 u_int32_t e2fs_first_dblock; /* first data block */ 140 u_int32_t e2fs_log_bsize; /* block size = 1024*(2^e2fs_log_bsize) */ 141 u_int32_t e2fs_fsize; /* fragment size */ 142 u_int32_t e2fs_bpg; /* blocks per group */ 143 u_int32_t e2fs_fpg; /* frags per group */ 144 u_int32_t e2fs_ipg; /* inodes per group */ 145 u_int32_t e2fs_mtime; /* mount time */ 146 u_int32_t e2fs_wtime; /* write time */ 147 u_int16_t e2fs_mnt_count; /* mount count */ 148 u_int16_t e2fs_max_mnt_count; /* max mount count */ 149 u_int16_t e2fs_magic; /* magic number */ 150 u_int16_t e2fs_state; /* file system state */ 151 u_int16_t e2fs_beh; /* behavior on errors */ 152 u_int16_t e2fs_minrev; /* minor revision level */ 153 u_int32_t e2fs_lastfsck; /* time of last fsck */ 154 u_int32_t e2fs_fsckintv; /* max time between fscks */ 155 u_int32_t e2fs_creator; /* creator OS */ 156 u_int32_t e2fs_rev; /* revision level */ 157 u_int16_t e2fs_ruid; /* default uid for reserved blocks */ 158 u_int16_t e2fs_rgid; /* default gid for reserved blocks */ 159 /* EXT2_DYNAMIC_REV superblocks */ 160 u_int32_t e2fs_first_ino; /* first non-reserved inode */ 161 u_int16_t e2fs_inode_size; /* size of inode structure */ 162 u_int16_t e2fs_block_group_nr; /* block grp number of this sblk*/ 163 u_int32_t e2fs_features_compat; /* compatible feature set */ 164 u_int32_t e2fs_features_incompat; /* incompatible feature set */ 165 u_int32_t e2fs_features_rocompat; /* RO-compatible feature set */ 166 u_int8_t e2fs_uuid[16]; /* 128-bit uuid for volume */ 167 char e2fs_vname[16]; /* volume name */ 168 char e2fs_fsmnt[64]; /* name mounted on */ 169 u_int32_t e2fs_algo; /* For compression */ 170 u_int8_t e2fs_prealloc; /* # of blocks to preallocate */ 171 u_int8_t e2fs_dir_prealloc; /* # of blocks to preallocate for dir */ 172 u_int16_t pad1; 173 u_int32_t reserved2[204]; 174 }; 175 176 177 /* in-memory data for ext2fs */ 178 struct m_ext2fs { 179 struct ext2fs e2fs; 180 u_char e2fs_fsmnt[MAXMNTLEN]; /* name mounted on */ 181 int8_t e2fs_ronly; /* mounted read-only flag */ 182 int8_t e2fs_fmod; /* super block modified flag */ 183 int32_t e2fs_bsize; /* block size */ 184 int32_t e2fs_bshift; /* ``lblkno'' calc of logical blkno */ 185 int32_t e2fs_bmask; /* ``blkoff'' calc of blk offsets */ 186 int64_t e2fs_qbmask; /* ~fs_bmask - for use with quad size */ 187 int32_t e2fs_fsbtodb; /* fsbtodb and dbtofsb shift constant */ 188 int32_t e2fs_ncg; /* number of cylinder groups */ 189 int32_t e2fs_ngdb; /* number of group descriptor block */ 190 int32_t e2fs_ipb; /* number of inodes per block */ 191 int32_t e2fs_itpg; /* number of inode table per group */ 192 struct ext2_gd *e2fs_gd; /* group descripors */ 193 }; 194 195 196 197 /* 198 * Filesystem identification 199 */ 200 #define E2FS_MAGIC 0xef53 /* the ext2fs magic number */ 201 #define E2FS_REV0 0 /* revision levels */ 202 #define E2FS_REV1 1 /* revision levels */ 203 204 /* compatible/imcompatible features */ 205 #define EXT2F_COMPAT_PREALLOC 0x0001 206 207 #define EXT2F_ROCOMPAT_SPARSESUPER 0x0001 208 #define EXT2F_ROCOMPAT_LARGEFILE 0x0002 209 #define EXT2F_ROCOMPAT_BTREE_DIR 0x0004 210 211 #define EXT2F_INCOMPAT_COMP 0x0001 212 #define EXT2F_INCOMPAT_FTYPE 0x0002 213 214 /* features supported in this implementation */ 215 #define EXT2F_COMPAT_SUPP 0x0000 216 #define EXT2F_ROCOMPAT_SUPP (EXT2F_ROCOMPAT_SPARSESUPER \ 217 | EXT2F_ROCOMPAT_LARGEFILE) 218 #define EXT2F_INCOMPAT_SUPP EXT2F_INCOMPAT_FTYPE 219 220 /* 221 * OS identification 222 */ 223 #define E2FS_OS_LINUX 0 224 #define E2FS_OS_HURD 1 225 #define E2FS_OS_MASIX 2 226 227 /* 228 * Filesystem clean flags 229 */ 230 #define E2FS_ISCLEAN 0x01 231 #define E2FS_ERRORS 0x02 232 233 /* ext2 file system block group descriptor */ 234 235 struct ext2_gd { 236 u_int32_t ext2bgd_b_bitmap; /* blocks bitmap block */ 237 u_int32_t ext2bgd_i_bitmap; /* inodes bitmap block */ 238 u_int32_t ext2bgd_i_tables; /* inodes table block */ 239 u_int16_t ext2bgd_nbfree; /* number of free blocks */ 240 u_int16_t ext2bgd_nifree; /* number of free inodes */ 241 u_int16_t ext2bgd_ndirs; /* number of directories */ 242 u_int16_t reserved; 243 u_int32_t reserved2[3]; 244 245 }; 246 247 248 /* 249 * If the EXT2F_ROCOMPAT_SPARSESUPER flag is set, the cylinder group has a 250 * copy of the super and cylinder group descriptors blocks only if it's 251 * a power of 3, 5 or 7 252 */ 253 254 static inline int cg_has_sb(int) __attribute__((__unused__)); 255 static inline int 256 cg_has_sb(i) 257 int i; 258 { 259 int a3 ,a5 , a7; 260 261 if (i == 0 || i == 1) 262 return 1; 263 for (a3 = 3, a5 = 5, a7 = 7; 264 a3 <= i || a5 <= i || a7 <= i; 265 a3 *= 3, a5 *= 5, a7 *= 7) 266 if (i == a3 || i == a5 || i == a7) 267 return 1; 268 return 0; 269 } 270 271 /* EXT2FS metadatas are stored in little-endian byte order. These macros 272 * helps reading theses metadatas 273 */ 274 275 #if BYTE_ORDER == LITTLE_ENDIAN 276 # define h2fs16(x) (x) 277 # define h2fs32(x) (x) 278 # define h2fs64(x) (x) 279 # define fs2h16(x) (x) 280 # define fs2h32(x) (x) 281 # define fs2h64(x) (x) 282 # define e2fs_sbload(old, new) memcpy((new), (old), SBSIZE); 283 # define e2fs_cgload(old, new, size) memcpy((new), (old), (size)); 284 # define e2fs_sbsave(old, new) memcpy((new), (old), SBSIZE); 285 # define e2fs_cgsave(old, new, size) memcpy((new), (old), (size)); 286 #else 287 void e2fs_sb_bswap(struct ext2fs *, struct ext2fs *); 288 void e2fs_cg_bswap(struct ext2_gd *, struct ext2_gd *, int); 289 # define h2fs16(x) bswap16(x) 290 # define h2fs32(x) bswap32(x) 291 # define h2fs64(x) bswap64(x) 292 # define fs2h16(x) bswap16(x) 293 # define fs2h32(x) bswap32(x) 294 # define fs2h64(x) bswap64(x) 295 # define e2fs_sbload(old, new) e2fs_sb_bswap((old), (new)) 296 # define e2fs_cgload(old, new, size) e2fs_cg_bswap((old), (new), (size)); 297 # define e2fs_sbsave(old, new) e2fs_sb_bswap((old), (new)) 298 # define e2fs_cgsave(old, new, size) e2fs_cg_bswap((old), (new), (size)); 299 #endif 300 301 /* 302 * Turn file system block numbers into disk block addresses. 303 * This maps file system blocks to device size blocks. 304 */ 305 #define fsbtodb(fs, b) ((b) << (fs)->e2fs_fsbtodb) 306 #define dbtofsb(fs, b) ((b) >> (fs)->e2fs_fsbtodb) 307 308 /* 309 * Macros for handling inode numbers: 310 * inode number to file system block offset. 311 * inode number to cylinder group number. 312 * inode number to file system block address. 313 */ 314 #define ino_to_cg(fs, x) (((x) - 1) / (fs)->e2fs.e2fs_ipg) 315 #define ino_to_fsba(fs, x) \ 316 ((fs)->e2fs_gd[ino_to_cg(fs, x)].ext2bgd_i_tables + \ 317 (((x)-1) % (fs)->e2fs.e2fs_ipg)/(fs)->e2fs_ipb) 318 #define ino_to_fsbo(fs, x) (((x)-1) % (fs)->e2fs_ipb) 319 320 /* 321 * Give cylinder group number for a file system block. 322 * Give cylinder group block number for a file system block. 323 */ 324 #define dtog(fs, d) (((d) - (fs)->e2fs.e2fs_first_dblock) / (fs)->e2fs.e2fs_fpg) 325 #define dtogd(fs, d) \ 326 (((d) - (fs)->e2fs.e2fs_first_dblock) % (fs)->e2fs.e2fs_fpg) 327 328 /* 329 * The following macros optimize certain frequently calculated 330 * quantities by using shifts and masks in place of divisions 331 * modulos and multiplications. 332 */ 333 #define blkoff(fs, loc) /* calculates (loc % fs->e2fs_bsize) */ \ 334 ((loc) & (fs)->e2fs_qbmask) 335 #define lblktosize(fs, blk) /* calculates (blk * fs->e2fs_bsize) */ \ 336 ((blk) << (fs)->e2fs_bshift) 337 #define lblkno(fs, loc) /* calculates (loc / fs->e2fs_bsize) */ \ 338 ((loc) >> (fs)->e2fs_bshift) 339 #define blkroundup(fs, size) /* calculates roundup(size, fs->e2fs_bsize) */ \ 340 (((size) + (fs)->e2fs_qbmask) & (fs)->e2fs_bmask) 341 #define fragroundup(fs, size) /* calculates roundup(size, fs->e2fs_bsize) */ \ 342 (((size) + (fs)->e2fs_qbmask) & (fs)->e2fs_bmask) 343 /* 344 * Determine the number of available frags given a 345 * percentage to hold in reserve. 346 */ 347 #define freespace(fs) \ 348 ((fs)->e2fs.e2fs_fbcount - (fs)->e2fs.e2fs_rbcount) 349 350 /* 351 * Number of indirects in a file system block. 352 */ 353 #define NINDIR(fs) ((fs)->e2fs_bsize / sizeof(u_int32_t)) 354 355 #endif /* !_UFS_EXT2FS_EXT2FS_H_ */ 356