ebc94b66fe
Reviewed by: pfg, gnn MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D19848
170 lines
6.0 KiB
C
170 lines
6.0 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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* SPDX-License-Identifier: BSD-3-Clause
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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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* 3. 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) ((daddr_t)(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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(e2fs_gd_get_i_tables(&(fs)->e2fs_gd[ino_to_cg((fs), (x))]) + \
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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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/*
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* Use if additional debug logging is required.
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*/
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/* #define EXT2FS_PRINT_EXTENTS */
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#endif /* !_FS_EXT2FS_FS_H_ */
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