b6113fb31a
In the ext2fs driver we have a mixture of headers: - The ext2_ prefixed headers have strong influence from NetBSD and are carry specific ext2/3/4 information. - The unprefixed headers are inspired on UFS and carry implementation specific information. Do some small adjustments so that the information is easier to find coming from either UFS or the NetBSD implementation. MFC after: 3 days
163 lines
5.8 KiB
C
163 lines
5.8 KiB
C
/*-
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* modified for EXT2FS support in Lites 1.1
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*
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* Aug 1995, Godmar Back (gback@cs.utah.edu)
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* University of Utah, Department of Computer Science
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*/
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/*-
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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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* 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 8.7 (Berkeley) 4/19/94
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* $FreeBSD$
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*/
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#ifndef _FS_EXT2FS_FS_H_
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#define _FS_EXT2FS_FS_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 SBSIZE 1024
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#define SBLOCK 2
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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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* A summary of contiguous blocks of various sizes is maintained
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* in each cylinder group. Normally this is set by the initial
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* value of fs_maxcontig.
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*
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* XXX:FS_MAXCONTIG is set to 16 to conserve space. Here we set
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* EXT2_MAXCONTIG to 32 for better performance.
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*/
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#define EXT2_MAXCONTIG 32
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/*
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* Grigoriy Orlov <gluk@ptci.ru> has done some extensive work to fine
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* tune the layout preferences for directories within a filesystem.
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* His algorithm can be tuned by adjusting the following parameters
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* which tell the system the average file size and the average number
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* of files per directory. These defaults are well selected for typical
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* filesystems, but may need to be tuned for odd cases like filesystems
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* being used for squid caches or news spools.
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* AVFPDIR is the expected number of files per directory. AVGDIRSIZE is
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* obtained by multiplying AVFPDIR and AVFILESIZ which is assumed to be
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* 16384.
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*/
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#define AFPDIR 64
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#define AVGDIRSIZE 1048576
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/*
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* Macros for access to superblock array structures
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*/
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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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/* get group containing inode */
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#define ino_to_cg(fs, x) (((x) - 1) / (fs->e2fs_ipg))
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/* get block containing inode from its number x */
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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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/* get offset for inode in block */
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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) / \
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EXT2_BLOCKS_PER_GROUP(fs))
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#define dtogd(fs, d) (((d) - fs->e2fs->e2fs_first_dblock) % \
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EXT2_BLOCKS_PER_GROUP(fs))
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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->fs_bsize) */ \
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((loc) & (fs)->e2fs_qbmask)
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#define lblktosize(fs, blk) /* calculates (blk * fs->fs_bsize) */ \
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((blk) << (fs->e2fs_bshift))
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#define lblkno(fs, loc) /* calculates (loc / fs->fs_bsize) */ \
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((loc) >> (fs->e2fs_bshift))
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/* no fragments -> logical block number equal # of frags */
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#define numfrags(fs, loc) /* calculates (loc / fs->fs_fsize) */ \
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((loc) >> (fs->e2fs_bshift))
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#define fragroundup(fs, size) /* calculates roundup(size, fs->fs_fsize) */ \
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roundup(size, fs->e2fs_fsize)
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/* was (((size) + (fs)->fs_qfmask) & (fs)->fs_fmask) */
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/*
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* Determining the size of a file block in the file system.
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* easy w/o fragments
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*/
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#define blksize(fs, ip, lbn) ((fs)->e2fs_fsize)
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/*
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* INOPB is the number of inodes in a secondary storage block.
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*/
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#define INOPB(fs) (fs->e2fs_ipb)
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/*
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* NINDIR is the number of indirects in a file system block.
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*/
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#define NINDIR(fs) (EXT2_ADDR_PER_BLOCK(fs))
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#endif /* !_FS_EXT2FS_FS_H_ */
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