/*-
 * 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       8.3 (Berkeley) 1/23/94
 * $FreeBSD: src/sys/isofs/cd9660/cd9660_bmap.c,v 1.8 1999/08/28 00:46:06 peter Exp $
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/vnode.h>
#include <sys/mount.h>

#include "iso.h"
#include "cd9660_node.h"

/*
 * Bmap converts 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.
 *
 * cd9660_bmap(struct vnode *a_vp, off_t a_loffset,
 *              off_t *a_doffsetp, int *a_runp, int *a_runb)
 */
int
cd9660_bmap(struct vop_bmap_args *ap)
{
        struct iso_node *ip = VTOI(ap->a_vp);
        off_t loffset = ap->a_loffset;
        int bshift;
        int bsize;

        /*
         * Check for underlying vnode requests and ensure that logical
         * to physical mapping is requested.
         */
        if (ap->a_doffsetp == NULL)
                return (0);

        /*
         * Compute the requested block number
         */
        bshift = ip->i_mnt->im_bshift;
        bsize = 1 << bshift;
        *ap->a_doffsetp = loffset + ((off_t)ip->iso_start << bshift);

        KKASSERT((loffset & (bsize - 1)) == 0);

        /*
         * Determine maximum number of readahead bytes following the
         * requested offset.  Align the result to the nearest block
         * boundary.  Do not count any non-full blocks(?)
         */
        if (ap->a_runp) {
                off_t nbytes;

                nbytes = (off_t)ip->i_size - loffset;
                if (nbytes < bsize)
                        *ap->a_runp = 0;
                else if (nbytes > MAXBSIZE)
                        *ap->a_runp = MAXBSIZE;
                else
                        *ap->a_runp = rounddown2((int)nbytes, bsize);
        }

        if (ap->a_runb) {
                *ap->a_runb = 0;
        }

        return 0;
}