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/* $NetBSD: cd9660_bmap.c,v 1.5 1994/12/13 22:33:12 mycroft Exp $ */
/*-
* Copyright (c) 1994
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley
* by Pace Willisson (pace@blitz.com). The Rock Ridge Extension
* Support code is derived from software contributed to Berkeley
* by Atsushi Murai (amurai@spec.co.jp).
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)cd9660_bmap.c 8.4 (Berkeley) 12/5/94
*/
#include <sys/param.h>
#include <sys/namei.h>
#include <sys/buf.h>
#include <sys/file.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <isofs/cd9660/iso.h>
#include <isofs/cd9660/cd9660_node.h>
/*
* Bmap converts a the logical block number of a file to its physical block
* number on the disk. The conversion is done by using the logical block
* number to index into the data block (extent) for the file.
*/
int
cd9660_bmap(ap)
struct vop_bmap_args /* {
struct vnode *a_vp;
daddr_t a_bn;
struct vnode **a_vpp;
daddr_t *a_bnp;
int *a_runp;
} */ *ap;
{
struct iso_node *ip = VTOI(ap->a_vp);
daddr_t lblkno = ap->a_bn;
int bshift;
/*
* Check for underlying vnode requests and ensure that logical
* to physical mapping is requested.
*/
if (ap->a_vpp != NULL)
*ap->a_vpp = ip->i_devvp;
if (ap->a_bnp == NULL)
return (0);
/*
* Compute the requested block number
*/
bshift = ip->i_mnt->im_bshift;
*ap->a_bnp = (ip->iso_start + lblkno) << (bshift - DEV_BSHIFT);
/*
* Determine maximum number of readahead blocks following the
* requested block.
*/
if (ap->a_runp) {
int nblk;
nblk = (ip->i_size >> bshift) - (lblkno + 1);
if (nblk <= 0)
*ap->a_runp = 0;
else if (nblk >= (MAXBSIZE >> bshift))
*ap->a_runp = (MAXBSIZE >> bshift) - 1;
else
*ap->a_runp = nblk;
}
return (0);
}
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