/*      $OpenBSD: cd9660_bmap.c,v 1.10 2021/03/05 07:01:36 jsg Exp $    */
/*      $NetBSD: cd9660_bmap.c,v 1.7 1997/01/24 00:27:29 cgd 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. 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/vnode.h>
#include <sys/lock.h>
#include <sys/mount.h>

#include <isofs/cd9660/iso.h>
#include <isofs/cd9660/cd9660_extern.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(void *v)
{
        struct vop_bmap_args *ap = v;
        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);
}