7abc12de03
- In ULCK_BUF we no longer need to acquire the lock, just write the buf out. - The combination of these changes eliminates one more use of B_LOCKED which is in the way of making the buffer cache SMP safe. In the long term ext2fs should probably not try to optimize the use of their metadata bufs with a private cache. This will starve the rest of the system for buffers in the extreme case. Discussed with: bde (A long time ago..) Tested on: md disk/x86
173 lines
6.1 KiB
C
173 lines
6.1 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) BUF_KERNPROC(bp);
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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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flags = (bp)->b_flags; \
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(bp)->b_flags &= ~(B_DIRTY); \
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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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