1 /* $OpenBSD: ext2fs.h,v 1.23 2016/04/27 11:27:24 krw Exp $ */ 2 /* $NetBSD: ext2fs.h,v 1.10 2000/01/28 16:00:23 bouyer Exp $ */ 3 4 /* 5 * Copyright (c) 1997 Manuel Bouyer. 6 * Copyright (c) 1982, 1986, 1993 7 * The Regents of the University of California. All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)fs.h 8.10 (Berkeley) 10/27/94 34 * Modified for ext2fs by Manuel Bouyer. 35 */ 36 37 #include <sys/endian.h> 38 39 /* 40 * Each disk drive contains some number of file systems. 41 * A file system consists of a number of cylinder groups. 42 * Each cylinder group has inodes and data. 43 * 44 * A file system is described by its super-block, which in turn 45 * describes the cylinder groups. The super-block is critical 46 * data and is replicated in each cylinder group to protect against 47 * catastrophic loss. This is done at `newfs' time and the critical 48 * super-block data does not change, so the copies need not be 49 * referenced further unless disaster strikes. 50 * 51 * The first boot and super blocks are given in absolute disk addresses. 52 * The byte-offset forms are preferred, as they don't imply a sector size. 53 */ 54 #define BBSIZE 1024 55 #define SBSIZE 1024 56 #define BBOFF ((off_t)(0)) 57 #define SBOFF ((off_t)(BBOFF + BBSIZE)) 58 #define BBLOCK ((daddr_t)(0)) 59 #define SBLOCK ((daddr_t)(BBLOCK + BBSIZE / DEV_BSIZE)) 60 61 /* 62 * Inodes are, like in UFS, 32-bit unsigned integers and therefore ufsino_t. 63 * Disk blocks are 32-bit, if the filesystem isn't operating in 64-bit mode 64 * (the incompatible ext4 64BIT flag). More work is needed to properly use 65 * daddr_t as the disk block data type on both BE and LE architectures. 66 * XXX disk blocks are simply u_int32_t for now. 67 */ 68 69 /* 70 * MINBSIZE is the smallest allowable block size. 71 * MINBSIZE must be big enough to hold a cylinder group block, 72 * thus changes to (struct cg) must keep its size within MINBSIZE. 73 * Note that super blocks are always of size SBSIZE, 74 * and that both SBSIZE and MAXBSIZE must be >= MINBSIZE. 75 * FSIZE means fragment size. 76 */ 77 #define LOG_MINBSIZE 10 78 #define MINBSIZE (1 << LOG_MINBSIZE) 79 #define LOG_MINFSIZE 10 80 #define MINFSIZE (1 << LOG_MINFSIZE) 81 82 /* 83 * The path name on which the file system is mounted is maintained 84 * in fs_fsmnt. MAXMNTLEN defines the amount of space allocated in 85 * the super block for this name. 86 */ 87 #define MAXMNTLEN 512 88 89 /* 90 * MINFREE gives the minimum acceptable percentage of file system 91 * blocks which may be free. If the freelist drops below this level 92 * only the superuser may continue to allocate blocks. This may 93 * be set to 0 if no reserve of free blocks is deemed necessary, 94 * however throughput drops by fifty percent if the file system 95 * is run at between 95% and 100% full; thus the minimum default 96 * value of fs_minfree is 5%. However, to get good clustering 97 * performance, 10% is a better choice. hence we use 10% as our 98 * default value. With 10% free space, fragmentation is not a 99 * problem, so we choose to optimize for time. 100 */ 101 #define MINFREE 5 102 103 /* 104 * Super block for an ext2fs file system. 105 */ 106 struct ext2fs { 107 u_int32_t e2fs_icount; /* Inode count */ 108 u_int32_t e2fs_bcount; /* blocks count */ 109 u_int32_t e2fs_rbcount; /* reserved blocks count */ 110 u_int32_t e2fs_fbcount; /* free blocks count */ 111 u_int32_t e2fs_ficount; /* free inodes count */ 112 u_int32_t e2fs_first_dblock; /* first data block */ 113 u_int32_t e2fs_log_bsize; /* block size = 1024*(2^e2fs_log_bsize) */ 114 u_int32_t e2fs_log_fsize; /* fragment size log2 */ 115 u_int32_t e2fs_bpg; /* blocks per group */ 116 u_int32_t e2fs_fpg; /* frags per group */ 117 u_int32_t e2fs_ipg; /* inodes per group */ 118 u_int32_t e2fs_mtime; /* mount time */ 119 u_int32_t e2fs_wtime; /* write time */ 120 u_int16_t e2fs_mnt_count; /* mount count */ 121 u_int16_t e2fs_max_mnt_count; /* max mount count */ 122 u_int16_t e2fs_magic; /* magic number */ 123 u_int16_t e2fs_state; /* file system state */ 124 u_int16_t e2fs_beh; /* behavior on errors */ 125 u_int16_t e2fs_minrev; /* minor revision level */ 126 u_int32_t e2fs_lastfsck; /* time of last fsck */ 127 u_int32_t e2fs_fsckintv; /* max time between fscks */ 128 u_int32_t e2fs_creator; /* creator OS */ 129 u_int32_t e2fs_rev; /* revision level */ 130 u_int16_t e2fs_ruid; /* default uid for reserved blocks */ 131 u_int16_t e2fs_rgid; /* default gid for reserved blocks */ 132 /* EXT2_DYNAMIC_REV superblocks */ 133 u_int32_t e2fs_first_ino; /* first non-reserved inode */ 134 u_int16_t e2fs_inode_size; /* size of inode structure */ 135 u_int16_t e2fs_block_group_nr; /* block grp number of this sblk*/ 136 u_int32_t e2fs_features_compat; /* compatible feature set */ 137 u_int32_t e2fs_features_incompat; /* incompatible feature set */ 138 u_int32_t e2fs_features_rocompat; /* RO-compatible feature set */ 139 u_int8_t e2fs_uuid[16]; /* 128-bit uuid for volume */ 140 char e2fs_vname[16]; /* volume name */ 141 char e2fs_fsmnt[64]; /* name mounted on */ 142 u_int32_t e2fs_algo; /* For compression */ 143 u_int8_t e2fs_prealloc; /* # of blocks to preallocate */ 144 u_int8_t e2fs_dir_prealloc; /* # of blocks to preallocate for dir */ 145 u_int16_t e2fs_reserved_ngdb; /* # of reserved gd blocks for resize */ 146 /* Ext3 JBD2 journaling. */ 147 u_int8_t e2fs_journal_uuid[16]; 148 u_int32_t e2fs_journal_ino; 149 u_int32_t e2fs_journal_dev; 150 u_int32_t e2fs_last_orphan; /* start of list of inodes to delete */ 151 u_int32_t e2fs_hash_seed[4]; /* htree hash seed */ 152 u_int8_t e2fs_def_hash_version; 153 u_int8_t e2fs_journal_backup_type; 154 u_int16_t e2fs_gdesc_size; 155 u_int32_t e2fs_default_mount_opts; 156 u_int32_t e2fs_first_meta_bg; 157 u_int32_t e2fs_mkfs_time; 158 u_int32_t e2fs_journal_backup[17]; 159 u_int32_t reserved2[172]; 160 }; 161 162 163 /* in-memory data for ext2fs */ 164 struct m_ext2fs { 165 struct ext2fs e2fs; 166 u_char e2fs_fsmnt[MAXMNTLEN]; /* name mounted on */ 167 int8_t e2fs_ronly; /* mounted read-only flag */ 168 int8_t e2fs_fmod; /* super block modified flag */ 169 int32_t e2fs_fsize; /* fragment size */ 170 int32_t e2fs_bsize; /* block size */ 171 int32_t e2fs_bshift; /* ``lblkno'' calc of logical blkno */ 172 int32_t e2fs_bmask; /* ``blkoff'' calc of blk offsets */ 173 int64_t e2fs_qbmask; /* ~fs_bmask - for use with quad size */ 174 int32_t e2fs_fsbtodb; /* fsbtodb and dbtofsb shift constant */ 175 int32_t e2fs_ncg; /* number of cylinder groups */ 176 int32_t e2fs_ngdb; /* number of group descriptor block */ 177 int32_t e2fs_ipb; /* number of inodes per block */ 178 int32_t e2fs_itpg; /* number of inode table per group */ 179 off_t e2fs_maxfilesize; /* depends on LARGE/HUGE flags */ 180 struct ext2_gd *e2fs_gd; /* group descriptors */ 181 }; 182 183 static inline int 184 e2fs_overflow(struct m_ext2fs *fs, off_t lower, off_t value) 185 { 186 return (value < lower || value > fs->e2fs_maxfilesize); 187 } 188 189 /* 190 * Filesystem identification 191 */ 192 #define E2FS_MAGIC 0xef53 /* the ext2fs magic number */ 193 #define E2FS_REV0 0 /* revision levels */ 194 #define E2FS_REV1 1 /* revision levels */ 195 196 /* compatible/imcompatible features */ 197 #define EXT2F_COMPAT_PREALLOC 0x0001 198 #define EXT2F_COMPAT_HASJOURNAL 0x0004 199 #define EXT2F_COMPAT_RESIZE 0x0010 200 #define EXT2F_COMPAT_DIRHASHINDEX 0x0020 201 202 203 #define EXT2F_ROCOMPAT_SPARSESUPER 0x0001 204 #define EXT2F_ROCOMPAT_LARGEFILE 0x0002 205 #define EXT2F_ROCOMPAT_BTREE_DIR 0x0004 206 #define EXT2F_ROCOMPAT_HUGE_FILE 0x0008 207 208 #define EXT2F_INCOMPAT_COMP 0x0001 209 #define EXT2F_INCOMPAT_FTYPE 0x0002 210 #define EXT2F_INCOMPAT_RECOVER 0x0004 211 #define EXT2F_INCOMPAT_JOURNAL_DEV 0x0008 212 #define EXT2F_INCOMPAT_META_BG 0x0010 213 #define EXT2F_INCOMPAT_EXTENTS 0x0040 214 #define EXT2F_INCOMPAT_FLEX_BG 0x0200 215 216 /* features supported in this implementation */ 217 #define EXT2F_COMPAT_SUPP 0x0000 218 #define EXT2F_ROCOMPAT_SUPP (EXT2F_ROCOMPAT_SPARSESUPER | \ 219 EXT2F_ROCOMPAT_LARGEFILE) 220 #define EXT2F_INCOMPAT_SUPP (EXT2F_INCOMPAT_FTYPE) 221 #define EXT4F_RO_INCOMPAT_SUPP (EXT2F_INCOMPAT_EXTENTS | \ 222 EXT2F_INCOMPAT_FLEX_BG | \ 223 EXT2F_INCOMPAT_META_BG | \ 224 EXT2F_INCOMPAT_RECOVER) 225 226 /* 227 * Definitions of behavior on errors 228 */ 229 #define E2FS_BEH_CONTINUE 1 /* continue operation */ 230 #define E2FS_BEH_READONLY 2 /* remount fs read only */ 231 #define E2FS_BEH_PANIC 3 /* cause panic */ 232 #define E2FS_BEH_DEFAULT E2FS_BEH_CONTINUE 233 234 /* 235 * OS identification 236 */ 237 #define E2FS_OS_LINUX 0 238 #define E2FS_OS_HURD 1 239 #define E2FS_OS_MASIX 2 240 241 /* 242 * Filesystem clean flags 243 */ 244 #define E2FS_ISCLEAN 0x01 245 #define E2FS_ERRORS 0x02 246 247 /* ext2 file system block group descriptor */ 248 249 struct ext2_gd { 250 u_int32_t ext2bgd_b_bitmap; /* blocks bitmap block */ 251 u_int32_t ext2bgd_i_bitmap; /* inodes bitmap block */ 252 u_int32_t ext2bgd_i_tables; /* inodes table block */ 253 u_int16_t ext2bgd_nbfree; /* number of free blocks */ 254 u_int16_t ext2bgd_nifree; /* number of free inodes */ 255 u_int16_t ext2bgd_ndirs; /* number of directories */ 256 u_int16_t reserved; 257 u_int32_t reserved2[3]; 258 }; 259 260 /* 261 * If the EXT2F_ROCOMPAT_SPARSESUPER flag is set, the cylinder group has a 262 * copy of the super and cylinder group descriptors blocks only if it's 263 * a power of 3, 5 or 7 264 */ 265 266 static __inline__ int cg_has_sb(int) __attribute__((__unused__)); 267 static __inline int 268 cg_has_sb(i) 269 int i; 270 { 271 int a3 ,a5 , a7; 272 273 if (i == 0 || i == 1) 274 return 1; 275 for (a3 = 3, a5 = 5, a7 = 7; 276 a3 <= i || a5 <= i || a7 <= i; 277 a3 *= 3, a5 *= 5, a7 *= 7) 278 if (i == a3 || i == a5 || i == a7) 279 return 1; 280 return 0; 281 } 282 283 /* 284 * Ext2 metadata is stored in little-endian byte order. 285 * JBD2 journal used in ext3 and ext4 is big-endian! 286 */ 287 #if BYTE_ORDER == LITTLE_ENDIAN 288 #define e2fs_sbload(old, new) memcpy((new), (old), SBSIZE); 289 #define e2fs_cgload(old, new, size) memcpy((new), (old), (size)); 290 #define e2fs_sbsave(old, new) memcpy((new), (old), SBSIZE); 291 #define e2fs_cgsave(old, new, size) memcpy((new), (old), (size)); 292 #else 293 void e2fs_sb_bswap(struct ext2fs *, struct ext2fs *); 294 void e2fs_cg_bswap(struct ext2_gd *, struct ext2_gd *, int); 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