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File: [cvs.NetBSD.org] / src / sys / fs / cd9660 / cd9660_bmap.c (download)

Revision 1.5, Sat Jun 14 07:39:28 2014 UTC (4 months, 1 week ago) by hannken
Branch: MAIN
CVS Tags: tls-maxphys-base, tls-earlyentropy-base, netbsd-7-base, netbsd-7, HEAD
Changes since 1.4: +3 -3 lines

Remove the hints "isodir" and "relocated" from cd9660_vget_internal()
and always reread the directory entry by inumber.  For directories
the directory entry is always its "." entry.

Always read directories via the device vnode to prevent buffer cache
inconsistency.  Keep i_devvp as a hint for fstat(1) and friends and
always use im_devvp for reads.  No need to vref()/vrele() i_devvp.

The additional bread is either cached because cd9660_lookup() just
released the buffer or will be used in the near future when the
directory gets traversed during lookup.

No objections on tech-kern@

/*	$NetBSD: cd9660_bmap.c,v 1.5 2014/06/14 07:39:28 hannken 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/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: cd9660_bmap.c,v 1.5 2014/06/14 07:39:28 hannken Exp $");

#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 <fs/cd9660/iso.h>
#include <fs/cd9660/cd9660_extern.h>
#include <fs/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 /* {
		struct vnode *a_vp;
		daddr_t  a_bn;
		struct vnode **a_vpp;
		daddr_t *a_bnp;
		int *a_runp;
	} */ *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_mnt->im_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);
}