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/* $OpenBSD: ext2fs.h,v 1.3 1997/06/12 21:09:30 downsj Exp $ */
/* $NetBSD: ext2fs.h,v 1.1 1997/06/11 09:33:37 bouyer Exp $ */
/*
* Copyright (c) 1997 Manuel Bouyer.
* Copyright (c) 1982, 1986, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)fs.h 8.10 (Berkeley) 10/27/94
* Modified for ext2fs by Manuel Bouyer.
*/
/*
* Each disk drive contains some number of file systems.
* A file system consists of a number of cylinder groups.
* Each cylinder group has inodes and data.
*
* A file system is described by its super-block, which in turn
* describes the cylinder groups. The super-block is critical
* data and is replicated in each cylinder group to protect against
* catastrophic loss. This is done at `newfs' time and the critical
* super-block data does not change, so the copies need not be
* referenced further unless disaster strikes.
*
* The first boot and super blocks are given in absolute disk addresses.
* The byte-offset forms are preferred, as they don't imply a sector size.
*/
#define BBSIZE 1024
#define SBSIZE 1024
#define BBOFF ((off_t)(0))
#define SBOFF ((off_t)(BBOFF + BBSIZE))
#define BBLOCK ((daddr_t)(0))
#define SBLOCK ((daddr_t)(BBLOCK + BBSIZE / DEV_BSIZE))
/*
* Addresses stored in inodes are capable of addressing blocks
* XXX
*/
/*
* MINBSIZE is the smallest allowable block size.
* MINBSIZE must be big enough to hold a cylinder group block,
* thus changes to (struct cg) must keep its size within MINBSIZE.
* Note that super blocks are always of size SBSIZE,
* and that both SBSIZE and MAXBSIZE must be >= MINBSIZE.
*/
#define LOG_MINBSIZE 10
#define MINBSIZE (1 << LOG_MINBSIZE)
/*
* The path name on which the file system is mounted is maintained
* in fs_fsmnt. MAXMNTLEN defines the amount of space allocated in
* the super block for this name.
*/
#define MAXMNTLEN 512
/*
* MINFREE gives the minimum acceptable percentage of file system
* blocks which may be free. If the freelist drops below this level
* only the superuser may continue to allocate blocks. This may
* be set to 0 if no reserve of free blocks is deemed necessary,
* however throughput drops by fifty percent if the file system
* is run at between 95% and 100% full; thus the minimum default
* value of fs_minfree is 5%. However, to get good clustering
* performance, 10% is a better choice. hence we use 10% as our
* default value. With 10% free space, fragmentation is not a
* problem, so we choose to optimize for time.
*/
#define MINFREE 5
/*
* Super block for an ext2fs file system.
*/
struct ext2fs {
u_int32_t e2fs_icount; /* Inode count */
u_int32_t e2fs_bcount; /* blocks count */
u_int32_t e2fs_rbcount; /* reserved blocks count */
u_int32_t e2fs_fbcount; /* free blocks count */
u_int32_t e2fs_ficount; /* free inodes count */
u_int32_t e2fs_first_dblock; /* first data block */
u_int32_t e2fs_log_bsize; /* block size = 1024*(2^e2fs_log_bsize) */
u_int32_t e2fs_fsize; /* fragment size */
u_int32_t e2fs_bpg; /* blocks per group */
u_int32_t e2fs_fpg; /* frags per group */
u_int32_t e2fs_ipg; /* inodes per group */
u_int32_t e2fs_mtime; /* mount time */
u_int32_t e2fs_wtime; /* write time */
u_int16_t e2fs_mnt_count; /* mount count */
u_int16_t e2fs_max_mnt_count; /* max mount count */
u_int16_t e2fs_magic; /* magic number */
u_int16_t e2fs_state; /* file system state */
u_int16_t e2fs_beh; /* behavior on errors */
u_int16_t reserved;
u_int32_t e2fs_lastfsck; /* time of last fsck */
u_int32_t e2fs_fsckintv; /* max time between fscks */
u_int32_t e2fs_creator; /* creator OS */
u_int32_t e2fs_rev; /* revision level */
u_int16_t e2fs_ruid; /* default uid for reserved blocks */
u_int16_t e2fs_rgid; /* default gid for reserved blocks */
u_int32_t reserved2[235];
};
/* in-memory data for ext2fs */
struct m_ext2fs {
struct ext2fs e2fs;
u_char e2fs_fsmnt[MAXMNTLEN]; /* name mounted on */
int8_t e2fs_ronly; /* mounted read-only flag */
int8_t e2fs_fmod; /* super block modified flag */
int32_t e2fs_bsize; /* block size */
int32_t e2fs_bshift; /* ``lblkno'' calc of logical blkno */
int32_t e2fs_bmask; /* ``blkoff'' calc of blk offsets */
int64_t e2fs_qbmask; /* ~fs_bmask - for use with quad size */
int32_t e2fs_fsbtodb; /* fsbtodb and dbtofsb shift constant */
int32_t e2fs_ncg; /* number of cylinder groups */
int32_t e2fs_ngdb; /* number of group descriptor block */
int32_t e2fs_ipb; /* number of inodes per block */
int32_t e2fs_itpg; /* number of inode table per group */
struct ext2_gd *e2fs_gd; /* group descripors */
};
/*
* Filesystem identification
*/
#define E2FS_MAGIC 0xef53 /* the ext2fs magic number */
#define E2FS_REV 0 /* revision level */
/*
* OS identification
*/
#define E2FS_OS_LINUX 0
#define E2FS_OS_HURD 1
#define E2FS_OS_MASIX 2
/*
* Filesystem clean flags
*/
#define E2FS_ISCLEAN 0x01
#define E2FS_ERRORS 0x02
/* ext2 file system block group descriptor */
struct ext2_gd {
u_int32_t ext2bgd_b_bitmap; /* blocks bitmap block */
u_int32_t ext2bgd_i_bitmap; /* inodes bitmap block */
u_int32_t ext2bgd_i_tables; /* inodes table block */
u_int16_t ext2bgd_nbfree; /* number of free blocks */
u_int16_t ext2bgd_nifree; /* number of free inodes */
u_int16_t ext2bgd_ndirs; /* number of directories */
u_int16_t reserved;
u_int32_t reserved2[3];
};
/*
* Turn file system block numbers into disk block addresses.
* This maps file system blocks to device size blocks.
*/
#define fsbtodb(fs, b) ((b) << (fs)->e2fs_fsbtodb)
#define dbtofsb(fs, b) ((b) >> (fs)->e2fs_fsbtodb)
/*
* Macros for handling inode numbers:
* inode number to file system block offset.
* inode number to cylinder group number.
* inode number to file system block address.
*/
#define ino_to_cg(fs, x) (((x) - 1) / (fs)->e2fs.e2fs_ipg)
#define ino_to_fsba(fs, x) \
((fs)->e2fs_gd[ino_to_cg(fs, x)].ext2bgd_i_tables + \
(((x)-1) % (fs)->e2fs.e2fs_ipg)/(fs)->e2fs_ipb)
#define ino_to_fsbo(fs, x) (((x)-1) % (fs)->e2fs_ipb)
/*
* Give cylinder group number for a file system block.
* Give cylinder group block number for a file system block.
*/
#define dtog(fs, d) (((d) - (fs)->e2fs.e2fs_first_dblock) / (fs)->e2fs.e2fs_fpg)
#define dtogd(fs, d) \
(((d) - (fs)->e2fs.e2fs_first_dblock) % (fs)->e2fs.e2fs_fpg)
/*
* The following macros optimize certain frequently calculated
* quantities by using shifts and masks in place of divisions
* modulos and multiplications.
*/
#define blkoff(fs, loc) /* calculates (loc % fs->e2fs_bsize) */ \
((loc) & (fs)->e2fs_qbmask)
#define lblktosize(fs, blk) /* calculates (blk * fs->e2fs_bsize) */ \
((blk) << (fs)->e2fs_bshift)
#define lblkno(fs, loc) /* calculates (loc / fs->e2fs_bsize) */ \
((loc) >> (fs)->e2fs_bshift)
#define blkroundup(fs, size) /* calculates roundup(size, fs->e2fs_bsize) */ \
(((size) + (fs)->e2fs_qbmask) & (fs)->e2fs_bmask)
#define fragroundup(fs, size) /* calculates roundup(size, fs->e2fs_bsize) */ \
(((size) + (fs)->e2fs_qbmask) & (fs)->e2fs_bmask)
/*
* Determine the number of available frags given a
* percentage to hold in reserve.
*/
#define freespace(fs) \
((fs)->e2fs.e2fs_fbcount - (fs)->e2fs.e2fs_rbcount)
/*
* Number of indirects in a file system block.
*/
#define NINDIR(fs) ((fs)->e2fs_bsize / sizeof(u_int32_t))
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