181 lines
6.2 KiB
C
181 lines
6.2 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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* 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 8.7 (Berkeley) 4/19/94
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* $FreeBSD$
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*/
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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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* Macros for access to superblock array structures
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*/
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/*
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* Convert cylinder group to base address of its global summary info.
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*/
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#define fs_cs(fs, cgindx) (((struct ext2_group_desc *) \
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(fs->s_group_desc[cgindx / EXT2_DESC_PER_BLOCK(fs)]->b_data)) \
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[cgindx % EXT2_DESC_PER_BLOCK(fs)])
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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)->s_fsbtodb))
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#define dbtofsb(fs, b) ((b) >> ((fs)->s_fsbtodb))
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/* get group containing inode */
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#define ino_to_cg(fs, x) (((x) - 1) / EXT2_INODES_PER_GROUP(fs))
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/* get block containing inode from its number x */
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#define ino_to_fsba(fs, x) fs_cs(fs, ino_to_cg(fs, x)).bg_inode_table + \
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(((x)-1) % EXT2_INODES_PER_GROUP(fs))/EXT2_INODES_PER_BLOCK(fs)
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/* get offset for inode in block */
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#define ino_to_fsbo(fs, x) ((x-1) % EXT2_INODES_PER_BLOCK(fs))
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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->s_es->s_first_data_block) / \
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EXT2_BLOCKS_PER_GROUP(fs))
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#define dtogd(fs, d) (((d) - fs->s_es->s_first_data_block) % \
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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)->s_qbmask)
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#define lblktosize(fs, blk) /* calculates (blk * fs->fs_bsize) */ \
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((blk) << (fs->s_bshift))
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#define lblkno(fs, loc) /* calculates (loc / fs->fs_bsize) */ \
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((loc) >> (fs->s_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->s_bshift))
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#define fragroundup(fs, size) /* calculates roundup(size, fs->fs_fsize) */ \
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roundup(size, fs->s_frag_size)
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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)->s_frag_size)
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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) EXT2_INODES_PER_BLOCK(fs)
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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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extern int inside[], around[];
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extern u_char *fragtbl[];
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/* a few remarks about superblock locking/unlocking
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* Linux provides special routines for doing so
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* I haven't figured out yet what BSD does
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* I think I'll try a VOP_LOCK/VOP_UNLOCK on the device vnode
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*/
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#define DEVVP(inode) (VFSTOEXT2(ITOV(inode)->v_mount)->um_devvp)
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#define lock_super(devvp) vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, curthread)
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#define unlock_super(devvp) VOP_UNLOCK(devvp, 0, curthread)
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/*
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* To lock a buffer, set the B_LOCKED flag and then brelse() it. To unlock,
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* reset the B_LOCKED flag and brelse() the buffer back on the LRU list
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*/
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#define LCK_BUF(bp) { \
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int s; \
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s = splbio(); \
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(bp)->b_flags |= B_LOCKED; \
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splx(s); \
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brelse(bp); \
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}
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#define ULCK_BUF(bp) { \
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long flags; \
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int s; \
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s = splbio(); \
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BUF_LOCK(bp, LK_EXCLUSIVE, NULL); \
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flags = (bp)->b_flags; \
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(bp)->b_flags &= ~(B_DIRTY | B_LOCKED); \
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bremfree(bp); \
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splx(s); \
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if (flags & B_DIRTY) \
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bwrite(bp); \
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else \
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brelse(bp); \
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}
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