ext2fs.h revision 1.29.12.1
1 /* $NetBSD: ext2fs.h,v 1.29.12.1 2012/10/30 17:22:59 yamt 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 * 47 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 48 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 49 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 50 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 51 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 52 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 53 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 54 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 55 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 56 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 57 * 58 * @(#)fs.h 8.10 (Berkeley) 10/27/94 59 * Modified for ext2fs by Manuel Bouyer. 60 */ 61 62 #ifndef _UFS_EXT2FS_EXT2FS_H_ 63 #define _UFS_EXT2FS_EXT2FS_H_ 64 65 #include <sys/bswap.h> 66 67 /* 68 * Each disk drive contains some number of file systems. 69 * A file system consists of a number of cylinder groups. 70 * Each cylinder group has inodes and data. 71 * 72 * A file system is described by its super-block, which in turn 73 * describes the cylinder groups. The super-block is critical 74 * data and is replicated in each cylinder group to protect against 75 * catastrophic loss. This is done at `newfs' time and the critical 76 * super-block data does not change, so the copies need not be 77 * referenced further unless disaster strikes. 78 * 79 * The first boot and super blocks are given in absolute disk addresses. 80 * The byte-offset forms are preferred, as they don't imply a sector size. 81 */ 82 #define BBSIZE 1024 83 #define SBSIZE 1024 84 #define BBOFF ((off_t)(0)) 85 #define SBOFF ((off_t)(BBOFF + BBSIZE)) 86 #define BBLOCK ((daddr_t)(0)) 87 #define SBLOCK ((daddr_t)(BBLOCK + BBSIZE / DEV_BSIZE)) 88 89 /* 90 * Addresses stored in inodes are capable of addressing blocks 91 * XXX 92 */ 93 94 /* 95 * MINBSIZE is the smallest allowable block size. 96 * MINBSIZE must be big enough to hold a cylinder group block, 97 * thus changes to (struct cg) must keep its size within MINBSIZE. 98 * Note that super blocks are always of size SBSIZE, 99 * and that both SBSIZE and MAXBSIZE must be >= MINBSIZE. 100 */ 101 #define LOG_MINBSIZE 10 102 #define MINBSIZE (1 << LOG_MINBSIZE) 103 104 /* 105 * The path name on which the file system is mounted is maintained 106 * in fs_fsmnt. MAXMNTLEN defines the amount of space allocated in 107 * the super block for this name. 108 */ 109 #define MAXMNTLEN 512 110 111 /* 112 * MINFREE gives the minimum acceptable percentage of file system 113 * blocks which may be free. If the freelist drops below this level 114 * only the superuser may continue to allocate blocks. This may 115 * be set to 0 if no reserve of free blocks is deemed necessary, 116 * however throughput drops by fifty percent if the file system 117 * is run at between 95% and 100% full; thus the minimum default 118 * value of fs_minfree is 5%. However, to get good clustering 119 * performance, 10% is a better choice. hence we use 10% as our 120 * default value. With 10% free space, fragmentation is not a 121 * problem, so we choose to optimize for time. 122 */ 123 #define MINFREE 5 124 125 /* 126 * Super block for an ext2fs file system. 127 */ 128 struct ext2fs { 129 uint32_t e2fs_icount; /* Inode count */ 130 uint32_t e2fs_bcount; /* blocks count */ 131 uint32_t e2fs_rbcount; /* reserved blocks count */ 132 uint32_t e2fs_fbcount; /* free blocks count */ 133 uint32_t e2fs_ficount; /* free inodes count */ 134 uint32_t e2fs_first_dblock; /* first data block */ 135 uint32_t e2fs_log_bsize; /* block size = 1024*(2^e2fs_log_bsize) */ 136 uint32_t e2fs_fsize; /* fragment size */ 137 uint32_t e2fs_bpg; /* blocks per group */ 138 uint32_t e2fs_fpg; /* frags per group */ 139 uint32_t e2fs_ipg; /* inodes per group */ 140 uint32_t e2fs_mtime; /* mount time */ 141 uint32_t e2fs_wtime; /* write time */ 142 uint16_t e2fs_mnt_count; /* mount count */ 143 uint16_t e2fs_max_mnt_count; /* max mount count */ 144 uint16_t e2fs_magic; /* magic number */ 145 uint16_t e2fs_state; /* file system state */ 146 uint16_t e2fs_beh; /* behavior on errors */ 147 uint16_t e2fs_minrev; /* minor revision level */ 148 uint32_t e2fs_lastfsck; /* time of last fsck */ 149 uint32_t e2fs_fsckintv; /* max time between fscks */ 150 uint32_t e2fs_creator; /* creator OS */ 151 uint32_t e2fs_rev; /* revision level */ 152 uint16_t e2fs_ruid; /* default uid for reserved blocks */ 153 uint16_t e2fs_rgid; /* default gid for reserved blocks */ 154 /* EXT2_DYNAMIC_REV superblocks */ 155 uint32_t e2fs_first_ino; /* first non-reserved inode */ 156 uint16_t e2fs_inode_size; /* size of inode structure */ 157 uint16_t e2fs_block_group_nr; /* block grp number of this sblk*/ 158 uint32_t e2fs_features_compat; /* compatible feature set */ 159 uint32_t e2fs_features_incompat; /* incompatible feature set */ 160 uint32_t e2fs_features_rocompat; /* RO-compatible feature set */ 161 uint8_t e2fs_uuid[16]; /* 128-bit uuid for volume */ 162 char e2fs_vname[16]; /* volume name */ 163 char e2fs_fsmnt[64]; /* name mounted on */ 164 uint32_t e2fs_algo; /* For compression */ 165 uint8_t e2fs_prealloc; /* # of blocks to preallocate */ 166 uint8_t e2fs_dir_prealloc; /* # of blocks to preallocate for dir */ 167 uint16_t e2fs_reserved_ngdb; /* # of reserved gd blocks for resize */ 168 uint32_t reserved2[204]; 169 }; 170 171 172 /* in-memory data for ext2fs */ 173 struct m_ext2fs { 174 struct ext2fs e2fs; 175 u_char e2fs_fsmnt[MAXMNTLEN]; /* name mounted on */ 176 int8_t e2fs_ronly; /* mounted read-only flag */ 177 int8_t e2fs_fmod; /* super block modified flag */ 178 int32_t e2fs_bsize; /* block size */ 179 int32_t e2fs_bshift; /* ``lblkno'' calc of logical blkno */ 180 int32_t e2fs_bmask; /* ``blkoff'' calc of blk offsets */ 181 int64_t e2fs_qbmask; /* ~fs_bmask - for use with quad size */ 182 int32_t e2fs_fsbtodb; /* fsbtodb and dbtofsb shift constant */ 183 int32_t e2fs_ncg; /* number of cylinder groups */ 184 int32_t e2fs_ngdb; /* number of group descriptor block */ 185 int32_t e2fs_ipb; /* number of inodes per block */ 186 int32_t e2fs_itpg; /* number of inode table per group */ 187 struct ext2_gd *e2fs_gd; /* group descripors */ 188 }; 189 190 191 192 /* 193 * Filesystem identification 194 */ 195 #define E2FS_MAGIC 0xef53 /* the ext2fs magic number */ 196 #define E2FS_REV0 0 /* GOOD_OLD revision */ 197 #define E2FS_REV1 1 /* Support compat/incompat features */ 198 199 /* compatible/incompatible features */ 200 #define EXT2F_COMPAT_PREALLOC 0x0001 201 #define EXT2F_COMPAT_AFS 0x0002 202 #define EXT2F_COMPAT_HASJOURNAL 0x0004 203 #define EXT2F_COMPAT_EXTATTR 0x0008 204 #define EXT2F_COMPAT_RESIZE 0x0010 205 #define EXT2F_COMPAT_DIRHASHINDEX 0x0020 206 #define EXT2F_COMPAT_BITS \ 207 "\20" \ 208 "\06COMPAT_DIRHASHINDEX" \ 209 "\05COMPAT_RESIZE" \ 210 "\04COMPAT_EXTATTR" \ 211 "\03COMPAT_HASJOURNAL" \ 212 "\02COMPAT_AFS" \ 213 "\01COMPAT_PREALLOC" 214 215 #define EXT2F_ROCOMPAT_SPARSESUPER 0x0001 216 #define EXT2F_ROCOMPAT_LARGEFILE 0x0002 217 #define EXT2F_ROCOMPAT_BTREE_DIR 0x0004 218 #define EXT2F_ROCOMPAT_BITS \ 219 "\20" \ 220 "\03ROCOMPAT_BTREE_DIR" \ 221 "\02ROCOMPAT_LARGEFILE" \ 222 "\01ROCOMPAT_SPARSEBUFFER" 223 224 #define EXT2F_INCOMPAT_COMP 0x0001 225 #define EXT2F_INCOMPAT_FTYPE 0x0002 226 #define EXT2F_INCOMPAT_REPLAY_JOURNAL 0x0004 227 #define EXT2F_INCOMPAT_USES_JOURNAL 0x0008 228 #define EXT2F_INCOMPAT_BITS \ 229 "\20" \ 230 "\04INCOMPAT_USES_JOURNAL" \ 231 "\03INCOMPAT_REPLAY_JOURNAL" \ 232 "\02INCOMPAT_FTYPE" \ 233 "\01INCOMPAT_COMP" 234 235 /* 236 * Features supported in this implementation 237 * 238 * We support the following REV1 features: 239 * - EXT2F_ROCOMPAT_SPARSESUPER 240 * superblock backups stored only in cg_has_sb(bno) groups 241 * - EXT2F_ROCOMPAT_LARGEFILE 242 * use e2di_dacl in struct ext2fs_dinode to store 243 * upper 32bit of size for >2GB files 244 * - EXT2F_INCOMPAT_FTYPE 245 * store file type to e2d_type in struct ext2fs_direct 246 * (on REV0 e2d_namlen is uint16_t and no e2d_type, like ffs) 247 */ 248 #define EXT2F_COMPAT_SUPP 0x0000 249 #define EXT2F_ROCOMPAT_SUPP (EXT2F_ROCOMPAT_SPARSESUPER \ 250 | EXT2F_ROCOMPAT_LARGEFILE) 251 #define EXT2F_INCOMPAT_SUPP EXT2F_INCOMPAT_FTYPE 252 253 /* 254 * Definitions of behavior on errors 255 */ 256 #define E2FS_BEH_CONTINUE 1 /* continue operation */ 257 #define E2FS_BEH_READONLY 2 /* remount fs read only */ 258 #define E2FS_BEH_PANIC 3 /* cause panic */ 259 #define E2FS_BEH_DEFAULT E2FS_BEH_CONTINUE 260 261 /* 262 * OS identification 263 */ 264 #define E2FS_OS_LINUX 0 265 #define E2FS_OS_HURD 1 266 #define E2FS_OS_MASIX 2 267 #define E2FS_OS_FREEBSD 3 268 #define E2FS_OS_LITES 4 269 270 /* 271 * Filesystem clean flags 272 */ 273 #define E2FS_ISCLEAN 0x01 274 #define E2FS_ERRORS 0x02 275 276 /* ext2 file system block group descriptor */ 277 278 struct ext2_gd { 279 uint32_t ext2bgd_b_bitmap; /* blocks bitmap block */ 280 uint32_t ext2bgd_i_bitmap; /* inodes bitmap block */ 281 uint32_t ext2bgd_i_tables; /* inodes table block */ 282 uint16_t ext2bgd_nbfree; /* number of free blocks */ 283 uint16_t ext2bgd_nifree; /* number of free inodes */ 284 uint16_t ext2bgd_ndirs; /* number of directories */ 285 uint16_t reserved; 286 uint32_t reserved2[3]; 287 }; 288 289 290 /* 291 * If the EXT2F_ROCOMPAT_SPARSESUPER flag is set, the cylinder group has a 292 * copy of the super and cylinder group descriptors blocks only if it's 293 * 1, a power of 3, 5 or 7 294 */ 295 296 static __inline int cg_has_sb(int) __unused; 297 static __inline int 298 cg_has_sb(int i) 299 { 300 int a3, a5, a7; 301 302 if (i == 0 || i == 1) 303 return 1; 304 for (a3 = 3, a5 = 5, a7 = 7; 305 a3 <= i || a5 <= i || a7 <= i; 306 a3 *= 3, a5 *= 5, a7 *= 7) 307 if (i == a3 || i == a5 || i == a7) 308 return 1; 309 return 0; 310 } 311 312 /* EXT2FS metadatas are stored in little-endian byte order. These macros 313 * helps reading theses metadatas 314 */ 315 316 #if BYTE_ORDER == LITTLE_ENDIAN 317 # define h2fs16(x) (x) 318 # define h2fs32(x) (x) 319 # define h2fs64(x) (x) 320 # define fs2h16(x) (x) 321 # define fs2h32(x) (x) 322 # define fs2h64(x) (x) 323 # define e2fs_sbload(old, new) memcpy((new), (old), SBSIZE); 324 # define e2fs_cgload(old, new, size) memcpy((new), (old), (size)); 325 # define e2fs_sbsave(old, new) memcpy((new), (old), SBSIZE); 326 # define e2fs_cgsave(old, new, size) memcpy((new), (old), (size)); 327 #else 328 void e2fs_sb_bswap(struct ext2fs *, struct ext2fs *); 329 void e2fs_cg_bswap(struct ext2_gd *, struct ext2_gd *, int); 330 # define h2fs16(x) bswap16(x) 331 # define h2fs32(x) bswap32(x) 332 # define h2fs64(x) bswap64(x) 333 # define fs2h16(x) bswap16(x) 334 # define fs2h32(x) bswap32(x) 335 # define fs2h64(x) bswap64(x) 336 # define e2fs_sbload(old, new) e2fs_sb_bswap((old), (new)) 337 # define e2fs_cgload(old, new, size) e2fs_cg_bswap((old), (new), (size)); 338 # define e2fs_sbsave(old, new) e2fs_sb_bswap((old), (new)) 339 # define e2fs_cgsave(old, new, size) e2fs_cg_bswap((old), (new), (size)); 340 #endif 341 342 /* 343 * Turn file system block numbers into disk block addresses. 344 * This maps file system blocks to device size blocks. 345 */ 346 #define fsbtodb(fs, b) ((b) << (fs)->e2fs_fsbtodb) 347 #define dbtofsb(fs, b) ((b) >> (fs)->e2fs_fsbtodb) 348 349 /* 350 * Macros for handling inode numbers: 351 * inode number to file system block offset. 352 * inode number to cylinder group number. 353 * inode number to file system block address. 354 */ 355 #define ino_to_cg(fs, x) (((x) - 1) / (fs)->e2fs.e2fs_ipg) 356 #define ino_to_fsba(fs, x) \ 357 ((fs)->e2fs_gd[ino_to_cg((fs), (x))].ext2bgd_i_tables + \ 358 (((x) - 1) % (fs)->e2fs.e2fs_ipg) / (fs)->e2fs_ipb) 359 #define ino_to_fsbo(fs, x) (((x) - 1) % (fs)->e2fs_ipb) 360 361 /* 362 * Give cylinder group number for a file system block. 363 * Give cylinder group block number for a file system block. 364 */ 365 #define dtog(fs, d) (((d) - (fs)->e2fs.e2fs_first_dblock) / (fs)->e2fs.e2fs_fpg) 366 #define dtogd(fs, d) \ 367 (((d) - (fs)->e2fs.e2fs_first_dblock) % (fs)->e2fs.e2fs_fpg) 368 369 /* 370 * The following macros optimize certain frequently calculated 371 * quantities by using shifts and masks in place of divisions 372 * modulos and multiplications. 373 */ 374 #define blkoff(fs, loc) /* calculates (loc % fs->e2fs_bsize) */ \ 375 ((loc) & (fs)->e2fs_qbmask) 376 #define lblktosize(fs, blk) /* calculates (blk * fs->e2fs_bsize) */ \ 377 ((blk) << (fs)->e2fs_bshift) 378 #define lblkno(fs, loc) /* calculates (loc / fs->e2fs_bsize) */ \ 379 ((loc) >> (fs)->e2fs_bshift) 380 #define blkroundup(fs, size) /* calculates roundup(size, fs->e2fs_bsize) */ \ 381 (((size) + (fs)->e2fs_qbmask) & (fs)->e2fs_bmask) 382 #define fragroundup(fs, size) /* calculates roundup(size, fs->e2fs_bsize) */ \ 383 (((size) + (fs)->e2fs_qbmask) & (fs)->e2fs_bmask) 384 /* 385 * Determine the number of available frags given a 386 * percentage to hold in reserve. 387 */ 388 #define freespace(fs) \ 389 ((fs)->e2fs.e2fs_fbcount - (fs)->e2fs.e2fs_rbcount) 390 391 /* 392 * Number of indirects in a file system block. 393 */ 394 #define NINDIR(fs) ((fs)->e2fs_bsize / sizeof(uint32_t)) 395 396 #endif /* !_UFS_EXT2FS_EXT2FS_H_ */ 397
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