319 lines
12 KiB
C
319 lines
12 KiB
C
/* $NetBSD: ext2fs.h,v 1.10 2000/01/28 16:00:23 bouyer Exp $ */
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/*
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* Copyright (c) 1997 Manuel Bouyer.
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* Copyright (c) 1982, 1986, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)fs.h 8.10 (Berkeley) 10/27/94
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* Modified for ext2fs by Manuel Bouyer.
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*/
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#include <machine/bswap.h>
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/*
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* Each disk drive contains some number of file systems.
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* A file system consists of a number of cylinder groups.
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* Each cylinder group has inodes and data.
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*
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* A file system is described by its super-block, which in turn
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* describes the cylinder groups. The super-block is critical
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* data and is replicated in each cylinder group to protect against
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* catastrophic loss. This is done at `newfs' time and the critical
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* super-block data does not change, so the copies need not be
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* referenced further unless disaster strikes.
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*
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* The first boot and super blocks are given in absolute disk addresses.
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* The byte-offset forms are preferred, as they don't imply a sector size.
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*/
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#define BBSIZE 1024
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#define SBSIZE 1024
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#define BBOFF ((off_t)(0))
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#define SBOFF ((off_t)(BBOFF + BBSIZE))
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#define BBLOCK ((ufs_daddr_t)(0))
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#define SBLOCK ((ufs_daddr_t)(BBLOCK + BBSIZE / DEV_BSIZE))
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/*
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* Addresses stored in inodes are capable of addressing blocks
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* XXX
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*/
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/*
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* MINBSIZE is the smallest allowable block size.
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* MINBSIZE must be big enough to hold a cylinder group block,
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* thus changes to (struct cg) must keep its size within MINBSIZE.
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* Note that super blocks are always of size SBSIZE,
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* and that both SBSIZE and MAXBSIZE must be >= MINBSIZE.
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*/
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#define LOG_MINBSIZE 10
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#define MINBSIZE (1 << LOG_MINBSIZE)
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/*
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* The path name on which the file system is mounted is maintained
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* in fs_fsmnt. MAXMNTLEN defines the amount of space allocated in
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* the super block for this name.
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*/
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#define MAXMNTLEN 512
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/*
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* MINFREE gives the minimum acceptable percentage of file system
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* blocks which may be free. If the freelist drops below this level
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* only the superuser may continue to allocate blocks. This may
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* be set to 0 if no reserve of free blocks is deemed necessary,
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* however throughput drops by fifty percent if the file system
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* is run at between 95% and 100% full; thus the minimum default
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* value of fs_minfree is 5%. However, to get good clustering
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* performance, 10% is a better choice. hence we use 10% as our
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* default value. With 10% free space, fragmentation is not a
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* problem, so we choose to optimize for time.
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*/
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#define MINFREE 5
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/*
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* Super block for an ext2fs file system.
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*/
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struct ext2fs {
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u_int32_t e2fs_icount; /* Inode count */
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u_int32_t e2fs_bcount; /* blocks count */
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u_int32_t e2fs_rbcount; /* reserved blocks count */
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u_int32_t e2fs_fbcount; /* free blocks count */
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u_int32_t e2fs_ficount; /* free inodes count */
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u_int32_t e2fs_first_dblock; /* first data block */
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u_int32_t e2fs_log_bsize; /* block size = 1024*(2^e2fs_log_bsize) */
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u_int32_t e2fs_fsize; /* fragment size */
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u_int32_t e2fs_bpg; /* blocks per group */
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u_int32_t e2fs_fpg; /* frags per group */
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u_int32_t e2fs_ipg; /* inodes per group */
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u_int32_t e2fs_mtime; /* mount time */
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u_int32_t e2fs_wtime; /* write time */
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u_int16_t e2fs_mnt_count; /* mount count */
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u_int16_t e2fs_max_mnt_count; /* max mount count */
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u_int16_t e2fs_magic; /* magic number */
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u_int16_t e2fs_state; /* file system state */
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u_int16_t e2fs_beh; /* behavior on errors */
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u_int16_t e2fs_minrev; /* minor revision level */
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u_int32_t e2fs_lastfsck; /* time of last fsck */
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u_int32_t e2fs_fsckintv; /* max time between fscks */
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u_int32_t e2fs_creator; /* creator OS */
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u_int32_t e2fs_rev; /* revision level */
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u_int16_t e2fs_ruid; /* default uid for reserved blocks */
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u_int16_t e2fs_rgid; /* default gid for reserved blocks */
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/* EXT2_DYNAMIC_REV superblocks */
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u_int32_t e2fs_first_ino; /* first non-reserved inode */
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u_int16_t e2fs_inode_size; /* size of inode structure */
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u_int16_t e2fs_block_group_nr; /* block grp number of this sblk*/
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u_int32_t e2fs_features_compat; /* compatible feature set */
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u_int32_t e2fs_features_incompat; /* incompatible feature set */
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u_int32_t e2fs_features_rocompat; /* RO-compatible feature set */
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u_int8_t e2fs_uuid[16]; /* 128-bit uuid for volume */
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char e2fs_vname[16]; /* volume name */
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char e2fs_fsmnt[64]; /* name mounted on */
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u_int32_t e2fs_algo; /* For compression */
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u_int8_t e2fs_prealloc; /* # of blocks to preallocate */
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u_int8_t e2fs_dir_prealloc; /* # of blocks to preallocate for dir */
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u_int16_t pad1;
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u_int32_t reserved2[204];
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};
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/* in-memory data for ext2fs */
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struct m_ext2fs {
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struct ext2fs e2fs;
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u_char e2fs_fsmnt[MAXMNTLEN]; /* name mounted on */
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int8_t e2fs_ronly; /* mounted read-only flag */
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int8_t e2fs_fmod; /* super block modified flag */
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int32_t e2fs_bsize; /* block size */
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int32_t e2fs_bshift; /* ``lblkno'' calc of logical blkno */
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int32_t e2fs_bmask; /* ``blkoff'' calc of blk offsets */
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int64_t e2fs_qbmask; /* ~fs_bmask - for use with quad size */
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int32_t e2fs_fsbtodb; /* fsbtodb and dbtofsb shift constant */
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int32_t e2fs_ncg; /* number of cylinder groups */
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int32_t e2fs_ngdb; /* number of group descriptor block */
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int32_t e2fs_ipb; /* number of inodes per block */
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int32_t e2fs_itpg; /* number of inode table per group */
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struct ext2_gd *e2fs_gd; /* group descripors */
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};
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/*
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* Filesystem identification
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*/
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#define E2FS_MAGIC 0xef53 /* the ext2fs magic number */
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#define E2FS_REV0 0 /* revision levels */
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#define E2FS_REV1 1 /* revision levels */
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/* compatible/imcompatible features */
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#define EXT2F_COMPAT_PREALLOC 0x0001
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#define EXT2F_ROCOMPAT_SPARSESUPER 0x0001
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#define EXT2F_ROCOMPAT_LARGEFILE 0x0002
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#define EXT2F_ROCOMPAT_BTREE_DIR 0x0004
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#define EXT2F_INCOMPAT_COMP 0x0001
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#define EXT2F_INCOMPAT_FTYPE 0x0002
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/* features supported in this implementation */
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#define EXT2F_COMPAT_SUPP 0x0000
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#define EXT2F_ROCOMPAT_SUPP EXT2F_ROCOMPAT_SPARSESUPER
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#define EXT2F_INCOMPAT_SUPP EXT2F_INCOMPAT_FTYPE
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/*
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* OS identification
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*/
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#define E2FS_OS_LINUX 0
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#define E2FS_OS_HURD 1
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#define E2FS_OS_MASIX 2
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/*
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* Filesystem clean flags
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*/
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#define E2FS_ISCLEAN 0x01
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#define E2FS_ERRORS 0x02
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/* ext2 file system block group descriptor */
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struct ext2_gd {
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u_int32_t ext2bgd_b_bitmap; /* blocks bitmap block */
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u_int32_t ext2bgd_i_bitmap; /* inodes bitmap block */
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u_int32_t ext2bgd_i_tables; /* inodes table block */
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u_int16_t ext2bgd_nbfree; /* number of free blocks */
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u_int16_t ext2bgd_nifree; /* number of free inodes */
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u_int16_t ext2bgd_ndirs; /* number of directories */
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u_int16_t reserved;
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u_int32_t reserved2[3];
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};
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/*
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* If the EXT2F_ROCOMPAT_SPARSESUPER flag is set, the cylinder group has a
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* copy of the super and cylinder group descriptors blocks only if it's
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* a power of 3, 5 or 7
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*/
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static __inline__ int cg_has_sb __P((int)) __attribute__((__unused__));
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static __inline int
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cg_has_sb(i)
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int i;
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{
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int a3 ,a5 , a7;
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if (i == 0 || i == 1)
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return 1;
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for (a3 = 3, a5 = 5, a7 = 7;
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a3 <= i || a5 <= i || a7 <= i;
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a3 *= 3, a5 *= 5, a7 *= 7)
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if (i == a3 || i == a5 || i == a7)
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return 1;
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return 0;
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}
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/* EXT2FS metadatas are stored in little-endian byte order. These macros
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* helps reading theses metadatas
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*/
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#if BYTE_ORDER == LITTLE_ENDIAN
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# define h2fs16(x) (x)
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# define h2fs32(x) (x)
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# define fs2h16(x) (x)
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# define fs2h32(x) (x)
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# define e2fs_sbload(old, new) memcpy((new), (old), SBSIZE);
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# define e2fs_cgload(old, new, size) memcpy((new), (old), (size));
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# define e2fs_sbsave(old, new) memcpy((new), (old), SBSIZE);
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# define e2fs_cgsave(old, new, size) memcpy((new), (old), (size));
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#else
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void e2fs_sb_bswap __P((struct ext2fs *, struct ext2fs *));
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void e2fs_cg_bswap __P((struct ext2_gd *, struct ext2_gd *, int));
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# define h2fs16(x) bswap16(x)
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# define h2fs32(x) bswap32(x)
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# define fs2h16(x) bswap16(x)
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# define fs2h32(x) bswap32(x)
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# define e2fs_sbload(old, new) e2fs_sb_bswap((old), (new))
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# define e2fs_cgload(old, new, size) e2fs_cg_bswap((old), (new), (size));
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# define e2fs_sbsave(old, new) e2fs_sb_bswap((old), (new))
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# define e2fs_cgsave(old, new, size) e2fs_cg_bswap((old), (new), (size));
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#endif
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/*
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* Turn file system block numbers into disk block addresses.
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* This maps file system blocks to device size blocks.
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*/
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#define fsbtodb(fs, b) ((b) << (fs)->e2fs_fsbtodb)
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#define dbtofsb(fs, b) ((b) >> (fs)->e2fs_fsbtodb)
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/*
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* Macros for handling inode numbers:
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* inode number to file system block offset.
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* inode number to cylinder group number.
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* inode number to file system block address.
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*/
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#define ino_to_cg(fs, x) (((x) - 1) / (fs)->e2fs.e2fs_ipg)
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#define ino_to_fsba(fs, x) \
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((fs)->e2fs_gd[ino_to_cg(fs, x)].ext2bgd_i_tables + \
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(((x)-1) % (fs)->e2fs.e2fs_ipg)/(fs)->e2fs_ipb)
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#define ino_to_fsbo(fs, x) (((x)-1) % (fs)->e2fs_ipb)
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/*
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* Give cylinder group number for a file system block.
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* Give cylinder group block number for a file system block.
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*/
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#define dtog(fs, d) (((d) - (fs)->e2fs.e2fs_first_dblock) / (fs)->e2fs.e2fs_fpg)
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#define dtogd(fs, d) \
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(((d) - (fs)->e2fs.e2fs_first_dblock) % (fs)->e2fs.e2fs_fpg)
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/*
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* The following macros optimize certain frequently calculated
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* quantities by using shifts and masks in place of divisions
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* modulos and multiplications.
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*/
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#define blkoff(fs, loc) /* calculates (loc % fs->e2fs_bsize) */ \
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((loc) & (fs)->e2fs_qbmask)
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#define lblktosize(fs, blk) /* calculates (blk * fs->e2fs_bsize) */ \
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((blk) << (fs)->e2fs_bshift)
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#define lblkno(fs, loc) /* calculates (loc / fs->e2fs_bsize) */ \
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((loc) >> (fs)->e2fs_bshift)
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#define blkroundup(fs, size) /* calculates roundup(size, fs->e2fs_bsize) */ \
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(((size) + (fs)->e2fs_qbmask) & (fs)->e2fs_bmask)
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#define fragroundup(fs, size) /* calculates roundup(size, fs->e2fs_bsize) */ \
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(((size) + (fs)->e2fs_qbmask) & (fs)->e2fs_bmask)
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/*
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* Determine the number of available frags given a
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* percentage to hold in reserve.
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*/
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#define freespace(fs) \
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((fs)->e2fs.e2fs_fbcount - (fs)->e2fs.e2fs_rbcount)
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/*
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* Number of indirects in a file system block.
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*/
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#define NINDIR(fs) ((fs)->e2fs_bsize / sizeof(u_int32_t))
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