1/* $OpenBSD: ext2fs.h,v 1.26 2021/03/11 13:31:35 jsg 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 */ 106struct 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 */ 164struct 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 183static inline int 184e2fs_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/incompatible features */ 197#define EXT2F_COMPAT_PREALLOC 0x0001 198#define EXT2F_COMPAT_IMAGIC_INODES 0x0002 199#define EXT2F_COMPAT_HAS_JOURNAL 0x0004 200#define EXT2F_COMPAT_EXT_ATTR 0x0008 201#define EXT2F_COMPAT_RESIZE 0x0010 202#define EXT2F_COMPAT_DIR_INDEX 0x0020 203#define EXT2F_COMPAT_SPARSE_SUPER2 0x0200 204 205#define EXT2F_ROCOMPAT_SPARSE_SUPER 0x0001 206#define EXT2F_ROCOMPAT_LARGE_FILE 0x0002 207#define EXT2F_ROCOMPAT_BTREE_DIR 0x0004 208#define EXT2F_ROCOMPAT_HUGE_FILE 0x0008 209#define EXT2F_ROCOMPAT_GDT_CSUM 0x0010 210#define EXT2F_ROCOMPAT_DIR_NLINK 0x0020 211#define EXT2F_ROCOMPAT_EXTRA_ISIZE 0x0040 212#define EXT2F_ROCOMPAT_QUOTA 0x0100 213#define EXT2F_ROCOMPAT_BIGALLOC 0x0200 214#define EXT2F_ROCOMPAT_METADATA_CKSUM 0x0400 215#define EXT2F_ROCOMPAT_READONLY 0x1000 216#define EXT2F_ROCOMPAT_PROJECT 0x2000 217 218#define EXT2F_INCOMPAT_COMP 0x0001 219#define EXT2F_INCOMPAT_FTYPE 0x0002 220#define EXT2F_INCOMPAT_RECOVER 0x0004 221#define EXT2F_INCOMPAT_JOURNAL_DEV 0x0008 222#define EXT2F_INCOMPAT_META_BG 0x0010 223#define EXT2F_INCOMPAT_EXTENTS 0x0040 224#define EXT2F_INCOMPAT_64BIT 0x0080 225#define EXT2F_INCOMPAT_MMP 0x0100 226#define EXT2F_INCOMPAT_FLEX_BG 0x0200 227#define EXT2F_INCOMPAT_EA_INODE 0x0400 228#define EXT2F_INCOMPAT_DIRDATA 0x1000 229#define EXT2F_INCOMPAT_CSUM_SEED 0x2000 230#define EXT2F_INCOMPAT_LARGEDIR 0x4000 231#define EXT2F_INCOMPAT_INLINE_DATA 0x8000 232#define EXT2F_INCOMPAT_ENCRYPT 0x10000 233 234struct ext2_feature { 235 uint32_t mask; 236 const char *name; 237}; 238 239static const struct ext2_feature ro_compat[] = { 240 { EXT2F_ROCOMPAT_SPARSE_SUPER, "sparse_super" }, 241 { EXT2F_ROCOMPAT_LARGE_FILE, "large_file" }, 242 { EXT2F_ROCOMPAT_BTREE_DIR, "btree_dir" }, 243 { EXT2F_ROCOMPAT_HUGE_FILE, "huge_file" }, 244 { EXT2F_ROCOMPAT_GDT_CSUM, "uninit_bg" }, 245 { EXT2F_ROCOMPAT_DIR_NLINK, "dir_nlink" }, 246 { EXT2F_ROCOMPAT_EXTRA_ISIZE, "extra_isize" }, 247 { EXT2F_ROCOMPAT_QUOTA, "quota" }, 248 { EXT2F_ROCOMPAT_BIGALLOC, "bigalloc" }, 249 { EXT2F_ROCOMPAT_METADATA_CKSUM, "metadata_csum" }, 250 { EXT2F_ROCOMPAT_READONLY, "read-only" }, 251 { EXT2F_ROCOMPAT_PROJECT, "project" } 252}; 253 254static const struct ext2_feature incompat[] = { 255 { EXT2F_INCOMPAT_COMP, "compression" }, 256 { EXT2F_INCOMPAT_FTYPE, "filetype" }, 257 { EXT2F_INCOMPAT_RECOVER, "needs_recovery" }, 258 { EXT2F_INCOMPAT_JOURNAL_DEV, "journal_dev" }, 259 { EXT2F_INCOMPAT_META_BG, "meta_bg" }, 260 { EXT2F_INCOMPAT_EXTENTS, "extents" }, 261 { EXT2F_INCOMPAT_64BIT, "64bit" }, 262 { EXT2F_INCOMPAT_MMP, "mmp" }, 263 { EXT2F_INCOMPAT_FLEX_BG, "flex_bg" }, 264 { EXT2F_INCOMPAT_EA_INODE, "ea_inode" }, 265 { EXT2F_INCOMPAT_DIRDATA, "dirdata" }, 266 { EXT2F_INCOMPAT_CSUM_SEED, "metadata_csum_seed" }, 267 { EXT2F_INCOMPAT_LARGEDIR, "large_dir" }, 268 { EXT2F_INCOMPAT_INLINE_DATA, "inline_data" }, 269 { EXT2F_INCOMPAT_ENCRYPT, "encrypt" } 270}; 271 272/* features supported in this implementation */ 273#define EXT2F_COMPAT_SUPP 0x0000 274#define EXT2F_ROCOMPAT_SUPP (EXT2F_ROCOMPAT_SPARSE_SUPER | \ 275 EXT2F_ROCOMPAT_LARGE_FILE) 276#define EXT2F_INCOMPAT_SUPP (EXT2F_INCOMPAT_FTYPE) 277#define EXT4F_RO_INCOMPAT_SUPP (EXT2F_INCOMPAT_EXTENTS | \ 278 EXT2F_INCOMPAT_FLEX_BG | \ 279 EXT2F_INCOMPAT_META_BG | \ 280 EXT2F_INCOMPAT_RECOVER) 281 282/* 283 * Definitions of behavior on errors 284 */ 285#define E2FS_BEH_CONTINUE 1 /* continue operation */ 286#define E2FS_BEH_READONLY 2 /* remount fs read only */ 287#define E2FS_BEH_PANIC 3 /* cause panic */ 288#define E2FS_BEH_DEFAULT E2FS_BEH_CONTINUE 289 290/* 291 * OS identification 292 */ 293#define E2FS_OS_LINUX 0 294#define E2FS_OS_HURD 1 295#define E2FS_OS_MASIX 2 296 297/* 298 * Filesystem clean flags 299 */ 300#define E2FS_ISCLEAN 0x01 301#define E2FS_ERRORS 0x02 302 303/* ext2 file system block group descriptor */ 304 305struct ext2_gd { 306 u_int32_t ext2bgd_b_bitmap; /* blocks bitmap block */ 307 u_int32_t ext2bgd_i_bitmap; /* inodes bitmap block */ 308 u_int32_t ext2bgd_i_tables; /* inodes table block */ 309 u_int16_t ext2bgd_nbfree; /* number of free blocks */ 310 u_int16_t ext2bgd_nifree; /* number of free inodes */ 311 u_int16_t ext2bgd_ndirs; /* number of directories */ 312 u_int16_t reserved; 313 u_int32_t reserved2[3]; 314}; 315 316/* 317 * If the EXT2F_ROCOMPAT_SPARSE_SUPER flag is set, the cylinder group has a 318 * copy of the super and cylinder group descriptors blocks only if it's 319 * a power of 3, 5 or 7 320 */ 321 322static __inline__ int cg_has_sb(int) __attribute__((__unused__)); 323static __inline int 324cg_has_sb(int i) 325{ 326 int a3 ,a5 , a7; 327 328 if (i == 0 || i == 1) 329 return 1; 330 for (a3 = 3, a5 = 5, a7 = 7; 331 a3 <= i || a5 <= i || a7 <= i; 332 a3 *= 3, a5 *= 5, a7 *= 7) 333 if (i == a3 || i == a5 || i == a7) 334 return 1; 335 return 0; 336} 337 338/* 339 * Ext2 metadata is stored in little-endian byte order. 340 * JBD2 journal used in ext3 and ext4 is big-endian! 341 */ 342#if BYTE_ORDER == LITTLE_ENDIAN 343#define e2fs_sbload(old, new) memcpy((new), (old), SBSIZE); 344#define e2fs_cgload(old, new, size) memcpy((new), (old), (size)); 345#define e2fs_sbsave(old, new) memcpy((new), (old), SBSIZE); 346#define e2fs_cgsave(old, new, size) memcpy((new), (old), (size)); 347#else 348void e2fs_sb_bswap(struct ext2fs *, struct ext2fs *); 349void e2fs_cg_bswap(struct ext2_gd *, struct ext2_gd *, int); 350#define e2fs_sbload(old, new) e2fs_sb_bswap((old), (new)) 351#define e2fs_cgload(old, new, size) e2fs_cg_bswap((old), (new), (size)); 352#define e2fs_sbsave(old, new) e2fs_sb_bswap((old), (new)) 353#define e2fs_cgsave(old, new, size) e2fs_cg_bswap((old), (new), (size)); 354#endif 355 356/* 357 * Turn file system block numbers into disk block addresses. 358 * This maps file system blocks to device size blocks. 359 */ 360#define fsbtodb(fs, b) ((b) << (fs)->e2fs_fsbtodb) 361#define dbtofsb(fs, b) ((b) >> (fs)->e2fs_fsbtodb) 362 363/* 364 * Macros for handling inode numbers: 365 * inode number to file system block offset. 366 * inode number to cylinder group number. 367 * inode number to file system block address. 368 */ 369#define ino_to_cg(fs, x) (((x) - 1) / (fs)->e2fs.e2fs_ipg) 370#define ino_to_fsba(fs, x) \ 371 ((fs)->e2fs_gd[ino_to_cg(fs, x)].ext2bgd_i_tables + \ 372 (((x)-1) % (fs)->e2fs.e2fs_ipg)/(fs)->e2fs_ipb) 373#define ino_to_fsbo(fs, x) (((x)-1) % (fs)->e2fs_ipb) 374 375/* 376 * Give cylinder group number for a file system block. 377 * Give cylinder group block number for a file system block. 378 */ 379#define dtog(fs, d) (((d) - (fs)->e2fs.e2fs_first_dblock) / (fs)->e2fs.e2fs_fpg) 380#define dtogd(fs, d) \ 381 (((d) - (fs)->e2fs.e2fs_first_dblock) % (fs)->e2fs.e2fs_fpg) 382 383/* 384 * The following macros optimize certain frequently calculated 385 * quantities by using shifts and masks in place of divisions 386 * modulos and multiplications. 387 */ 388#define blkoff(fs, loc) /* calculates (loc % fs->e2fs_bsize) */ \ 389 ((loc) & (fs)->e2fs_qbmask) 390#define lblktosize(fs, blk) /* calculates (blk * fs->e2fs_bsize) */ \ 391 ((blk) << (fs)->e2fs_bshift) 392#define lblkno(fs, loc) /* calculates (loc / fs->e2fs_bsize) */ \ 393 ((loc) >> (fs)->e2fs_bshift) 394#define blkroundup(fs, size) /* calculates roundup(size, fs->e2fs_bsize) */ \ 395 (((size) + (fs)->e2fs_qbmask) & (fs)->e2fs_bmask) 396#define fragroundup(fs, size) /* calculates roundup(size, fs->e2fs_bsize) */ \ 397 (((size) + (fs)->e2fs_qbmask) & (fs)->e2fs_bmask) 398/* 399 * Determine the number of available frags given a 400 * percentage to hold in reserve. 401 */ 402#define freespace(fs) \ 403 ((fs)->e2fs.e2fs_fbcount - (fs)->e2fs.e2fs_rbcount) 404 405/* 406 * Number of indirects in a file system block. 407 */ 408#define NINDIR(fs) ((fs)->e2fs_bsize / sizeof(u_int32_t)) 409