File:  [DragonFly] / src / sys / vfs / isofs / cd9660 / cd9660_bmap.c
Revision 1.6: download - view: text, annotated - select for diffs
Mon Aug 13 17:31:56 2007 UTC (7 years, 1 month ago) by dillon
Branches: MAIN
CVS tags: HEAD, DragonFly_RELEASE_2_0_Slip, DragonFly_RELEASE_2_0, DragonFly_RELEASE_1_12_Slip, DragonFly_RELEASE_1_12, DragonFly_Preview
Remove the vpp (returned underlying device vnode) argument from VOP_BMAP().
VOP_BMAP() may now only be used to determine linearity and clusterability of
the blocks underlying a filesystem object.  The meaning of the returned
block number (other then being contiguous as a means of indicating
linearity or clusterability) is now up to the VFS.

This removes visibility into the device(s) underlying a filesystem from
the rest of the kernel.

/*-
 * 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	8.3 (Berkeley) 1/23/94
 * $FreeBSD: src/sys/isofs/cd9660/cd9660_bmap.c,v 1.8 1999/08/28 00:46:06 peter Exp $
 * $DragonFly: src/sys/vfs/isofs/cd9660/cd9660_bmap.c,v 1.6 2007/08/13 17:31:56 dillon 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 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.
 *
 * 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 = (int)nbytes & ~(bsize - 1);
	}
	if (ap->a_runb) {
		*ap->a_runb = 0;
	}
	return 0;
}