126 lines
3.5 KiB
C
126 lines
3.5 KiB
C
/* $NetBSD: bmap.c,v 1.3 1994/10/27 04:21:48 cgd Exp $ */
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/*
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* Copyright (c) 1982, 1986, 1989 Regents of the University of California.
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* 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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* @(#)ufs_bmap.c 7.13 (Berkeley) 5/8/91
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*/
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#include "param.h"
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#include "dinode.h"
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#include "fs.h"
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#include "errno.h"
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/*
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* Bmap converts a the logical block number of a file
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* to its physical block number on the disk. The conversion
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* is done by using the logical block number to index into
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* the array of block pointers described by the dinode.
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*/
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extern struct fs *fs;
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extern int bdev;
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static daddr_t bap[2*1024];
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static daddr_t bnobap;
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bmap(dip, bn, bnp)
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register struct dinode *dip;
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register daddr_t bn;
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daddr_t *bnp;
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{
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register daddr_t nb;
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int i, j, sh;
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int error;
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/*fprintf(stderr, "bmap %d ", bn);*/
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if (bn < 0)
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return (EFBIG);
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/*
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* The first NDADDR blocks are direct blocks
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*/
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if (bn < NDADDR) {
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nb = dip->di_db[bn];
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if (nb == 0) {
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*bnp = (daddr_t)-1;
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/*fprintf(stderr, "%d\n", *bnp);*/
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return (0);
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}
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*bnp = fsbtodb(fs, nb);
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/*fprintf(stderr, "%d\n", *bnp);*/
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return (0);
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}
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/*
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* Determine the number of levels of indirection.
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*/
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sh = 1;
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bn -= NDADDR;
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for (j = NIADDR; j > 0; j--) {
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sh *= NINDIR(fs);
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if (bn < sh)
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break;
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bn -= sh;
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}
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if (j == 0)
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return (EFBIG);
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/*
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* Fetch through the indirect blocks.
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*/
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nb = dip->di_ib[NIADDR - j];
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if (nb == 0) {
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*bnp = (daddr_t)-1;
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/*fprintf(stderr, "%d\n", *bnp);*/
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return (0);
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}
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for (; j <= NIADDR; j++) {
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daddr_t bno = fsbtodb(fs, nb);
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if (bnobap != bno &&
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(error = bread(bdev, bno, &bap,
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(int)fs->fs_bsize))) {
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return (error);
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}
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bnobap = bno;
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sh /= NINDIR(fs);
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i = (bn / sh) % NINDIR(fs);
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nb = bap[i];
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if (nb == 0) {
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*bnp = (daddr_t)-1;
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/*fprintf(stderr, "%d\n", *bnp);*/
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return (0);
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}
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}
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*bnp = fsbtodb(fs, nb);
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/*fprintf(stderr, "%d\n", *bnp);*/
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return (0);
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}
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