109 lines
3.5 KiB
C
109 lines
3.5 KiB
C
/*-
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* Copyright (c) 1994
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley
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* by Pace Willisson (pace@blitz.com). The Rock Ridge Extension
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* Support code is derived from software contributed to Berkeley
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* by Atsushi Murai (amurai@spec.co.jp).
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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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* @(#)cd9660_bmap.c 8.3 (Berkeley) 1/23/94
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* $Id: cd9660_bmap.c,v 1.2 1994/08/02 07:41:15 davidg Exp $
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*/
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#include <sys/param.h>
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#include <sys/namei.h>
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#include <sys/buf.h>
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#include <sys/file.h>
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#include <sys/vnode.h>
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#include <sys/mount.h>
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#include <isofs/cd9660/iso.h>
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#include <isofs/cd9660/cd9660_node.h>
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/*
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* Bmap converts a the logical block number of a file to its physical block
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* number on the disk. The conversion is done by using the logical block
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* number to index into the data block (extent) for the file.
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*/
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int
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cd9660_bmap(ap)
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struct vop_bmap_args /* {
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struct vnode *a_vp;
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daddr_t a_bn;
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struct vnode **a_vpp;
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daddr_t *a_bnp;
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int *a_runp;
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int *a_runb;
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} */ *ap;
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{
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struct iso_node *ip = VTOI(ap->a_vp);
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daddr_t lblkno = ap->a_bn;
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long bsize;
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/*
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* Check for underlying vnode requests and ensure that logical
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* to physical mapping is requested.
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*/
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if (ap->a_vpp != NULL)
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*ap->a_vpp = ip->i_devvp;
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if (ap->a_bnp == NULL)
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return (0);
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/*
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* Compute the requested block number
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*/
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bsize = ip->i_mnt->logical_block_size;
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*ap->a_bnp = (ip->iso_start + lblkno) * btodb(bsize);
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/*
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* Determine maximum number of readahead blocks following the
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* requested block.
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*/
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if (ap->a_runp) {
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int nblk;
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nblk = (ip->i_size - (lblkno + 1) * bsize) / bsize;
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if (nblk <= 0)
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*ap->a_runp = 0;
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else if (nblk >= MAXBSIZE/bsize)
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*ap->a_runp = MAXBSIZE/bsize - 1;
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else
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*ap->a_runp = nblk;
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}
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if (ap->a_runb) {
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*ap->a_runb = 0;
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}
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return 0;
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}
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