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ext2fs.h revision 1.45
      1 /*	$NetBSD: ext2fs.h,v 1.45 2016/08/14 11:42:50 jdolecek 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 #define	fsbtodb(fs, b)  ((daddr_t)(b) << (fs)->e2fs_fsbtodb)
     90 /* calculates (loc / fs->fs_bsize) */
     91 #define	lblkno(fs, loc) ((loc) >> (fs->e2fs_bshift))
     92 #define	blksize(fs, ip, lbn) ((fs)->e2fs_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 	uint32_t  e2fs_icount;		/* Inode count */
    135 	uint32_t  e2fs_bcount;		/* blocks count */
    136 	uint32_t  e2fs_rbcount;		/* reserved blocks count */
    137 	uint32_t  e2fs_fbcount;		/* free blocks count */
    138 	uint32_t  e2fs_ficount;		/* free inodes count */
    139 	uint32_t  e2fs_first_dblock;	/* first data block */
    140 	uint32_t  e2fs_log_bsize;	/* bsize = 1024*(2^e2fs_log_bsize) */
    141 	uint32_t  e2fs_fsize;		/* fragment size */
    142 	uint32_t  e2fs_bpg;		/* blocks per group */
    143 	uint32_t  e2fs_fpg;		/* frags per group */
    144 	uint32_t  e2fs_ipg;		/* inodes per group */
    145 	uint32_t  e2fs_mtime;		/* mount time */
    146 	uint32_t  e2fs_wtime;		/* write time */
    147 	uint16_t  e2fs_mnt_count;	/* mount count */
    148 	uint16_t  e2fs_max_mnt_count;	/* max mount count */
    149 	uint16_t  e2fs_magic;		/* magic number */
    150 	uint16_t  e2fs_state;		/* file system state */
    151 	uint16_t  e2fs_beh;		/* behavior on errors */
    152 	uint16_t  e2fs_minrev;		/* minor revision level */
    153 	uint32_t  e2fs_lastfsck;	/* time of last fsck */
    154 	uint32_t  e2fs_fsckintv;	/* max time between fscks */
    155 	uint32_t  e2fs_creator;		/* creator OS */
    156 	uint32_t  e2fs_rev;		/* revision level */
    157 	uint16_t  e2fs_ruid;		/* default uid for reserved blocks */
    158 	uint16_t  e2fs_rgid;		/* default gid for reserved blocks */
    159 	/* EXT2_DYNAMIC_REV superblocks */
    160 	uint32_t  e2fs_first_ino;	/* first non-reserved inode */
    161 	uint16_t  e2fs_inode_size;	/* size of inode structure */
    162 	uint16_t  e2fs_block_group_nr;	/* block grp number of this sblk*/
    163 	uint32_t  e2fs_features_compat;	/*  compatible feature set */
    164 	uint32_t  e2fs_features_incompat; /* incompatible feature set */
    165 	uint32_t  e2fs_features_rocompat; /* RO-compatible feature set */
    166 	uint8_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 	uint32_t  e2fs_algo;		/* For compression */
    170 	uint8_t   e2fs_prealloc;	/* # of blocks to preallocate */
    171 	uint8_t   e2fs_dir_prealloc;	/* # of blocks to preallocate for dir */
    172 	uint16_t  e2fs_reserved_ngdb;	/* # of reserved gd blocks for resize */
    173 
    174 	/* Additional fields */
    175 	char      e3fs_journal_uuid[16];/* uuid of journal superblock */
    176 	uint32_t  e3fs_journal_inum;	/* inode number of journal file */
    177 	uint32_t  e3fs_journal_dev;	/* device number of journal file */
    178 	uint32_t  e3fs_last_orphan;	/* start of list of inodes to delete */
    179 	uint32_t  e3fs_hash_seed[4];	/* HTREE hash seed */
    180 	char      e3fs_def_hash_version;/* Default hash version to use */
    181 	char      e3fs_jnl_backup_type;
    182 	uint16_t  e3fs_desc_size;	/* size of group descriptor */
    183 	uint32_t  e3fs_default_mount_opts;
    184 	uint32_t  e3fs_first_meta_bg;	/* First metablock block group */
    185 	uint32_t  e3fs_mkfs_time;	/* when the fs was created */
    186 	uint32_t  e3fs_jnl_blks[17];	/* backup of the journal inode */
    187 	uint32_t  e4fs_bcount_hi;	/* high bits of blocks count */
    188 	uint32_t  e4fs_rbcount_hi;	/* high bits of reserved blocks count */
    189 	uint32_t  e4fs_fbcount_hi;	/* high bits of free blocks count */
    190 	uint16_t  e4fs_min_extra_isize; /* all inodes have some bytes */
    191 	uint16_t  e4fs_want_extra_isize;/* inodes must reserve some bytes */
    192 	uint32_t  e4fs_flags;		/* miscellaneous flags */
    193 	uint16_t  e4fs_raid_stride;	/* RAID stride */
    194 	uint16_t  e4fs_mmpintv;		/* seconds to wait in MMP checking */
    195 	uint64_t  e4fs_mmpblk;		/* block for multi-mount protection */
    196 	uint32_t  e4fs_raid_stripe_wid; /* blocks on data disks (N * stride) */
    197 	uint8_t   e4fs_log_gpf;		/* FLEX_BG group size */
    198 	uint8_t   e4fs_chksum_type;	/* metadata checksum algorithm used */
    199 	uint8_t   e4fs_encrypt;		/* versioning level for encryption */
    200 	uint8_t   e4fs_reserved_pad;
    201 	uint64_t  e4fs_kbytes_written;	/* number of lifetime kilobytes */
    202 	uint32_t  e4fs_snapinum;	/* inode number of active snapshot */
    203 	uint32_t  e4fs_snapid;		/* sequential ID of active snapshot */
    204 	uint64_t  e4fs_snaprbcount;	/* rsvd blocks for active snapshot */
    205 	uint32_t  e4fs_snaplist;	/* inode number for on-disk snapshot */
    206 	uint32_t  e4fs_errcount;	/* number of file system errors */
    207 	uint32_t  e4fs_first_errtime;	/* first time an error happened */
    208 	uint32_t  e4fs_first_errino;	/* inode involved in first error */
    209 	uint64_t  e4fs_first_errblk;	/* block involved of first error */
    210 	uint8_t   e4fs_first_errfunc[32];/* function where error happened */
    211 	uint32_t  e4fs_first_errline;	/* line number where error happened */
    212 	uint32_t  e4fs_last_errtime;	/* most recent time of an error */
    213 	uint32_t  e4fs_last_errino;	/* inode involved in last error */
    214 	uint32_t  e4fs_last_errline;	/* line number where error happened */
    215 	uint64_t  e4fs_last_errblk;	/* block involved of last error */
    216 	uint8_t   e4fs_last_errfunc[32];/* function where error happened */
    217 	uint8_t   e4fs_mount_opts[64];
    218 	uint32_t  e4fs_usrquota_inum;	/* inode for tracking user quota */
    219 	uint32_t  e4fs_grpquota_inum;	/* inode for tracking group quota */
    220 	uint32_t  e4fs_overhead_clusters;/* overhead blocks/clusters */
    221 	uint32_t  e4fs_backup_bgs[2];	/* groups with sparse_super2 SBs */
    222 	uint8_t   e4fs_encrypt_algos[4];/* encryption algorithms in use */
    223 	uint8_t   e4fs_encrypt_pw_salt[16];/* salt used for string2key */
    224 	uint32_t  e4fs_lpf_ino;		/* location of the lost+found inode */
    225 	uint32_t  e4fs_proj_quota_inum;	/* inode for tracking project quota */
    226 	uint32_t  e4fs_chksum_seed;	/* checksum seed */
    227 	uint32_t  e4fs_reserved[98];	/* padding to the end of the block */
    228 	uint32_t  e4fs_sbchksum;	/* superblock checksum */
    229 };
    230 
    231 
    232 /* in-memory data for ext2fs */
    233 struct m_ext2fs {
    234 	struct ext2fs e2fs;
    235 	u_char	e2fs_fsmnt[MAXMNTLEN];	/* name mounted on */
    236 	int8_t	e2fs_ronly;	/* mounted read-only flag */
    237 	int8_t	e2fs_fmod;	/* super block modified flag */
    238 	int8_t	e2fs_uhash;	/* 3 if hash should be signed, 0 if not */
    239 	int32_t	e2fs_bsize;	/* block size */
    240 	int32_t e2fs_bshift;	/* ``lblkno'' calc of logical blkno */
    241 	int32_t e2fs_bmask;	/* ``blkoff'' calc of blk offsets */
    242 	int64_t e2fs_qbmask;	/* ~fs_bmask - for use with quad size */
    243 	int32_t	e2fs_fsbtodb;	/* fsbtodb and dbtofsb shift constant */
    244 	int32_t	e2fs_ncg;	/* number of cylinder groups */
    245 	int32_t	e2fs_ngdb;	/* number of group descriptor block */
    246 	int32_t	e2fs_ipb;	/* number of inodes per block */
    247 	int32_t	e2fs_itpg;	/* number of inode table per group */
    248 	struct	ext2_gd *e2fs_gd; /* group descripors */
    249 };
    250 
    251 
    252 
    253 /*
    254  * Filesystem identification
    255  */
    256 #define	E2FS_MAGIC	0xef53	/* the ext2fs magic number */
    257 #define E2FS_REV0	0	/* GOOD_OLD revision */
    258 #define E2FS_REV1	1	/* Support compat/incompat features */
    259 
    260 /* compatible/incompatible features */
    261 #define EXT2F_COMPAT_PREALLOC		0x0001
    262 #define EXT2F_COMPAT_AFS		0x0002
    263 #define EXT2F_COMPAT_HASJOURNAL		0x0004
    264 #define EXT2F_COMPAT_EXTATTR		0x0008
    265 #define EXT2F_COMPAT_RESIZE		0x0010
    266 #define EXT2F_COMPAT_DIRHASHINDEX	0x0020
    267 #define EXT2F_COMPAT_SPARSESUPER2	0x0200
    268 #define	EXT2F_COMPAT_BITS \
    269 	"\20" \
    270 	"\12COMPAT_SPARSESUPER2" \
    271 	"\11" \
    272 	"\10" \
    273 	"\07" \
    274 	"\06COMPAT_DIRHASHINDEX" \
    275 	"\05COMPAT_RESIZE" \
    276 	"\04COMPAT_EXTATTR" \
    277 	"\03COMPAT_HASJOURNAL" \
    278 	"\02COMPAT_AFS" \
    279 	"\01COMPAT_PREALLOC"
    280 
    281 #define EXT2F_ROCOMPAT_SPARSESUPER	0x0001
    282 #define EXT2F_ROCOMPAT_LARGEFILE	0x0002
    283 #define EXT2F_ROCOMPAT_BTREE_DIR	0x0004
    284 #define EXT2F_ROCOMPAT_HUGE_FILE	0x0008
    285 #define EXT2F_ROCOMPAT_GDT_CSUM		0x0010
    286 #define EXT2F_ROCOMPAT_DIR_NLINK	0x0020
    287 #define EXT2F_ROCOMPAT_EXTRA_ISIZE	0x0040
    288 #define EXT2F_ROCOMPAT_QUOTA		0x0100
    289 #define EXT2F_ROCOMPAT_BIGALLOC		0x0200
    290 #define EXT2F_ROCOMPAT_METADATA_CKSUM	0x0400
    291 #define EXT2F_ROCOMPAT_READONLY		0x1000
    292 #define EXT2F_ROCOMPAT_PROJECT		0x2000
    293 #define	EXT2F_ROCOMPAT_BITS \
    294 	"\20" \
    295 	"\16ROCOMPAT_PROJECT" \
    296 	"\15ROCOMPAT_READONLY" \
    297 	"\14" \
    298 	"\13ROCOMPAT_METADATA_CKSUM" \
    299 	"\12ROCOMPAT_BIGALLOC" \
    300 	"\11ROCOMPAT_QUOTA" \
    301 	"\10" \
    302 	"\07ROCOMPAT_EXTRA_ISIZE" \
    303 	"\06ROCOMPAT_DIR_NLINK" \
    304 	"\05ROCOMPAT_GDT_CSUM" \
    305 	"\04ROCOMPAT_HUGE_FILE" \
    306 	"\03ROCOMPAT_BTREE_DIR" \
    307 	"\02ROCOMPAT_LARGEFILE" \
    308 	"\01ROCOMPAT_SPARSESUPER"
    309 
    310 #define EXT2F_INCOMPAT_COMP		0x0001
    311 #define EXT2F_INCOMPAT_FTYPE		0x0002
    312 #define	EXT2F_INCOMPAT_REPLAY_JOURNAL	0x0004
    313 #define	EXT2F_INCOMPAT_USES_JOURNAL	0x0008
    314 #define EXT2F_INCOMPAT_META_BG		0x0010
    315 #define EXT2F_INCOMPAT_EXTENTS		0x0040
    316 #define EXT2F_INCOMPAT_64BIT		0x0080
    317 #define EXT2F_INCOMPAT_MMP		0x0100
    318 #define EXT2F_INCOMPAT_FLEX_BG		0x0200
    319 #define EXT2F_INCOMPAT_EA_INODE		0x0400
    320 #define EXT2F_INCOMPAT_DIRDATA		0x1000
    321 #define EXT2F_INCOMPAT_CSUM_SEED	0x2000
    322 #define EXT2F_INCOMPAT_LARGEDIR		0x4000
    323 #define EXT2F_INCOMPAT_INLINE_DATA	0x8000
    324 #define EXT2F_INCOMPAT_ENCRYPT		0x10000
    325 #define	EXT2F_INCOMPAT_BITS \
    326 	"\20" \
    327 	"\021INCOMPAT_ENCRYPT" \
    328 	"\020INCOMPAT_INLINE_DATA" \
    329 	"\017INCOMPAT_LARGEDIR" \
    330 	"\016INCOMPAT_CSUM_SEED" \
    331 	"\015INCOMPAT_DIRDATA" \
    332 	"\014" \
    333 	"\013INCOMPAT_EA_INODE" \
    334 	"\012INCOMPAT_FLEX_BG" \
    335 	"\011INCOMPAT_MMP" \
    336 	"\010INCOMPAT_64BIT" \
    337 	"\07INCOMPAT_EXTENTS" \
    338 	"\05INCOMPAT_META_BG" \
    339 	"\04INCOMPAT_USES_JOURNAL" \
    340 	"\03INCOMPAT_REPLAY_JOURNAL" \
    341 	"\02INCOMPAT_FTYPE" \
    342 	"\01INCOMPAT_COMP"
    343 
    344 /*
    345  * Features supported in this implementation
    346  *
    347  * We support the following REV1 features:
    348  * - EXT2F_ROCOMPAT_SPARSESUPER
    349  *    superblock backups stored only in cg_has_sb(bno) groups
    350  * - EXT2F_ROCOMPAT_LARGEFILE
    351  *    use e2di_size_high in struct ext2fs_dinode to store
    352  *    upper 32bit of size for >2GB files
    353  * - EXT2F_INCOMPAT_FTYPE
    354  *    store file type to e2d_type in struct ext2fs_direct
    355  *    (on REV0 e2d_namlen is uint16_t and no e2d_type, like ffs)
    356  */
    357 #define EXT2F_COMPAT_SUPP		0x0000
    358 #define EXT2F_ROCOMPAT_SUPP		(EXT2F_ROCOMPAT_SPARSESUPER \
    359 					 | EXT2F_ROCOMPAT_LARGEFILE \
    360 					 | EXT2F_ROCOMPAT_HUGE_FILE \
    361 					 | EXT2F_ROCOMPAT_EXTRA_ISIZE)
    362 #define EXT2F_INCOMPAT_SUPP		(EXT2F_INCOMPAT_FTYPE \
    363 					 | EXT2F_INCOMPAT_EXTENTS)
    364 
    365 /*
    366  * Feature set definitions
    367  */
    368 #define EXT2F_HAS_COMPAT_FEATURE(fs, feature) \
    369 	((fs)->e2fs.e2fs_rev >= E2FS_REV1 && \
    370 	((fs)->e2fs.e2fs_features_compat & (feature)) != 0)
    371 
    372 #define EXT2F_HAS_ROCOMPAT_FEATURE(fs, feature) \
    373 	((fs)->e2fs.e2fs_rev >= E2FS_REV1 && \
    374 	((fs)->e2fs.e2fs_features_rocompat & (feature)) != 0)
    375 
    376 #define EXT2F_HAS_INCOMPAT_FEATURE(fs, feature) \
    377 	((fs)->e2fs.e2fs_rev >= E2FS_REV1 && \
    378 	((fs)->e2fs.e2fs_features_incompat & (feature)) != 0)
    379 
    380 
    381 /*
    382  * Definitions of behavior on errors
    383  */
    384 #define E2FS_BEH_CONTINUE	1	/* continue operation */
    385 #define E2FS_BEH_READONLY	2	/* remount fs read only */
    386 #define E2FS_BEH_PANIC		3	/* cause panic */
    387 #define E2FS_BEH_DEFAULT	E2FS_BEH_CONTINUE
    388 
    389 /*
    390  * OS identification
    391  */
    392 #define E2FS_OS_LINUX	0
    393 #define E2FS_OS_HURD	1
    394 #define E2FS_OS_MASIX	2
    395 #define E2FS_OS_FREEBSD	3
    396 #define E2FS_OS_LITES	4
    397 
    398 /*
    399  * Filesystem clean flags
    400  */
    401 #define	E2FS_ISCLEAN	0x01
    402 #define	E2FS_ERRORS	0x02
    403 
    404 /* ext2 file system block group descriptor */
    405 
    406 struct ext2_gd {
    407 	uint32_t ext2bgd_b_bitmap;	/* blocks bitmap block */
    408 	uint32_t ext2bgd_i_bitmap;	/* inodes bitmap block */
    409 	uint32_t ext2bgd_i_tables;	/* inodes table block  */
    410 	uint16_t ext2bgd_nbfree;	/* number of free blocks */
    411 	uint16_t ext2bgd_nifree;	/* number of free inodes */
    412 	uint16_t ext2bgd_ndirs;		/* number of directories */
    413 	uint16_t reserved;
    414 	uint32_t reserved2[3];
    415 };
    416 
    417 
    418 /*
    419  * If the EXT2F_ROCOMPAT_SPARSESUPER flag is set, the cylinder group has a
    420  * copy of the super and cylinder group descriptors blocks only if it's
    421  * 1, a power of 3, 5 or 7
    422  */
    423 
    424 static __inline int cg_has_sb(int) __unused;
    425 static __inline int
    426 cg_has_sb(int i)
    427 {
    428 	int a3, a5, a7;
    429 
    430 	if (i == 0 || i == 1)
    431 		return 1;
    432 	for (a3 = 3, a5 = 5, a7 = 7;
    433 	    a3 <= i || a5 <= i || a7 <= i;
    434 	    a3 *= 3, a5 *= 5, a7 *= 7)
    435 		if (i == a3 || i == a5 || i == a7)
    436 			return 1;
    437 	return 0;
    438 }
    439 
    440 /* EXT2FS metadatas are stored in little-endian byte order. These macros
    441  * helps reading theses metadatas
    442  */
    443 
    444 #if BYTE_ORDER == LITTLE_ENDIAN
    445 #	define h2fs16(x) (x)
    446 #	define h2fs32(x) (x)
    447 #	define h2fs64(x) (x)
    448 #	define fs2h16(x) (x)
    449 #	define fs2h32(x) (x)
    450 #	define fs2h64(x) (x)
    451 #	define e2fs_sbload(old, new) memcpy((new), (old), SBSIZE);
    452 #	define e2fs_cgload(old, new, size) memcpy((new), (old), (size));
    453 #	define e2fs_sbsave(old, new) memcpy((new), (old), SBSIZE);
    454 #	define e2fs_cgsave(old, new, size) memcpy((new), (old), (size));
    455 #else
    456 void e2fs_sb_bswap(struct ext2fs *, struct ext2fs *);
    457 void e2fs_cg_bswap(struct ext2_gd *, struct ext2_gd *, int);
    458 #	define h2fs16(x) bswap16(x)
    459 #	define h2fs32(x) bswap32(x)
    460 #	define h2fs64(x) bswap64(x)
    461 #	define fs2h16(x) bswap16(x)
    462 #	define fs2h32(x) bswap32(x)
    463 #	define fs2h64(x) bswap64(x)
    464 #	define e2fs_sbload(old, new) e2fs_sb_bswap((old), (new))
    465 #	define e2fs_cgload(old, new, size) e2fs_cg_bswap((old), (new), (size));
    466 #	define e2fs_sbsave(old, new) e2fs_sb_bswap((old), (new))
    467 #	define e2fs_cgsave(old, new, size) e2fs_cg_bswap((old), (new), (size));
    468 #endif
    469 
    470 /*
    471  * Turn file system block numbers into disk block addresses.
    472  * This maps file system blocks to device size blocks.
    473  */
    474 #define EXT2_FSBTODB(fs, b)	((b) << (fs)->e2fs_fsbtodb)
    475 #define EXT2_DBTOFSB(fs, b)	((b) >> (fs)->e2fs_fsbtodb)
    476 
    477 /*
    478  * Macros for handling inode numbers:
    479  *	 inode number to file system block offset.
    480  *	 inode number to cylinder group number.
    481  *	 inode number to file system block address.
    482  */
    483 #define	ino_to_cg(fs, x)	(((x) - 1) / (fs)->e2fs.e2fs_ipg)
    484 #define	ino_to_fsba(fs, x)						\
    485 	((fs)->e2fs_gd[ino_to_cg((fs), (x))].ext2bgd_i_tables +		\
    486 	(((x) - 1) % (fs)->e2fs.e2fs_ipg) / (fs)->e2fs_ipb)
    487 #define	ino_to_fsbo(fs, x)	(((x) - 1) % (fs)->e2fs_ipb)
    488 
    489 /*
    490  * Give cylinder group number for a file system block.
    491  * Give cylinder group block number for a file system block.
    492  */
    493 #define	dtog(fs, d) (((d) - (fs)->e2fs.e2fs_first_dblock) / (fs)->e2fs.e2fs_fpg)
    494 #define	dtogd(fs, d) \
    495 	(((d) - (fs)->e2fs.e2fs_first_dblock) % (fs)->e2fs.e2fs_fpg)
    496 
    497 /*
    498  * The following macros optimize certain frequently calculated
    499  * quantities by using shifts and masks in place of divisions
    500  * modulos and multiplications.
    501  */
    502 #define ext2_blkoff(fs, loc)	/* calculates (loc % fs->e2fs_bsize) */ \
    503 	((loc) & (fs)->e2fs_qbmask)
    504 #define ext2_lblktosize(fs, blk) /* calculates (blk * fs->e2fs_bsize) */ \
    505 	((blk) << (fs)->e2fs_bshift)
    506 #define ext2_lblkno(fs, loc)	/* calculates (loc / fs->e2fs_bsize) */ \
    507 	((loc) >> (fs)->e2fs_bshift)
    508 #define ext2_blkroundup(fs, size) /* calculates roundup(size, fs->e2fs_bsize) */ \
    509 	(((size) + (fs)->e2fs_qbmask) & (fs)->e2fs_bmask)
    510 #define ext2_fragroundup(fs, size) /* calculates roundup(size, fs->e2fs_bsize) */ \
    511 	(((size) + (fs)->e2fs_qbmask) & (fs)->e2fs_bmask)
    512 /*
    513  * Determine the number of available frags given a
    514  * percentage to hold in reserve.
    515  */
    516 #define freespace(fs) \
    517    ((fs)->e2fs.e2fs_fbcount - (fs)->e2fs.e2fs_rbcount)
    518 
    519 /*
    520  * Number of indirects in a file system block.
    521  */
    522 #define	EXT2_NINDIR(fs)	((fs)->e2fs_bsize / sizeof(uint32_t))
    523 
    524 #endif /* !_UFS_EXT2FS_EXT2FS_H_ */
    525