104 lines
2.9 KiB
C
104 lines
2.9 KiB
C
/*
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* Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009, 2014
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* The President and Fellows of Harvard College.
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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 UNIVERSITY 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 UNIVERSITY 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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/*
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* SFS filesystem
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*
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* Block allocation.
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*/
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#include <types.h>
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#include <lib.h>
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#include <bitmap.h>
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#include <sfs.h>
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#include "sfsprivate.h"
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/*
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* Zero out a disk block.
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*/
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static
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int
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sfs_clearblock(struct sfs_fs *sfs, daddr_t block)
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{
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/* static -> automatically initialized to zero */
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static char zeros[SFS_BLOCKSIZE];
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return sfs_writeblock(sfs, block, zeros, SFS_BLOCKSIZE);
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}
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/*
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* Allocate a block.
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*/
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int
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sfs_balloc(struct sfs_fs *sfs, daddr_t *diskblock)
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{
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int result;
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result = bitmap_alloc(sfs->sfs_freemap, diskblock);
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if (result) {
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return result;
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}
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sfs->sfs_freemapdirty = true;
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if (*diskblock >= sfs->sfs_sb.sb_nblocks) {
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panic("sfs: %s: balloc: invalid block %u\n",
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sfs->sfs_sb.sb_volname, *diskblock);
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}
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/* Clear block before returning it */
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result = sfs_clearblock(sfs, *diskblock);
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if (result) {
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bitmap_unmark(sfs->sfs_freemap, *diskblock);
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}
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return result;
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}
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/*
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* Free a block.
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*/
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void
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sfs_bfree(struct sfs_fs *sfs, daddr_t diskblock)
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{
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bitmap_unmark(sfs->sfs_freemap, diskblock);
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sfs->sfs_freemapdirty = true;
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}
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/*
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* Check if a block is in use.
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*/
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int
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sfs_bused(struct sfs_fs *sfs, daddr_t diskblock)
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{
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if (diskblock >= sfs->sfs_sb.sb_nblocks) {
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panic("sfs: %s: sfs_bused called on out of range block %u\n",
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sfs->sfs_sb.sb_volname, diskblock);
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}
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return bitmap_isset(sfs->sfs_freemap, diskblock);
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}
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