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/* $NetBSD: ufs_bmap.c,v 1.14 2004/06/20 22:20:18 jmc Exp $ */
/* From: NetBSD: ufs_bmap.c,v 1.14 2001/11/08 05:00:51 chs Exp */
/*
* Copyright (c) 1989, 1991, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* 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.
*
* @(#)ufs_bmap.c 8.8 (Berkeley) 8/11/95
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/time.h>
#include <assert.h>
#include <errno.h>
#include <strings.h>
#include "makefs.h"
#include <ufs/ufs/dinode.h>
#include <ufs/ffs/fs.h>
#include "ffs/ufs_bswap.h"
#include "ffs/ufs_inode.h"
#include "ffs/ffs_extern.h"
/*
* Create an array of logical block number/offset pairs which represent the
* path of indirect blocks required to access a data block. The first "pair"
* contains the logical block number of the appropriate single, double or
* triple indirect block and the offset into the inode indirect block array.
* Note, the logical block number of the inode single/double/triple indirect
* block appears twice in the array, once with the offset into the i_ffs_ib and
* once with the offset into the page itself.
*/
int
ufs_getlbns(struct inode *ip, daddr_t bn, struct indir *ap, int *nump)
{
daddr_t metalbn, realbn;
int64_t blockcnt;
int lbc;
int i, numlevels, off;
u_long lognindir;
lognindir = ffs(NINDIR(ip->i_fs)) - 1;
if (nump)
*nump = 0;
numlevels = 0;
realbn = bn;
if ((long)bn < 0)
bn = -(long)bn;
assert (bn >= NDADDR);
/*
* Determine the number of levels of indirection. After this loop
* is done, blockcnt indicates the number of data blocks possible
* at the given level of indirection, and NIADDR - i is the number
* of levels of indirection needed to locate the requested block.
*/
bn -= NDADDR;
for (lbc = 0, i = NIADDR;; i--, bn -= blockcnt) {
if (i == 0)
return (EFBIG);
lbc += lognindir;
blockcnt = (int64_t)1 << lbc;
if (bn < blockcnt)
break;
}
/* Calculate the address of the first meta-block. */
if (realbn >= 0)
metalbn = -(realbn - bn + NIADDR - i);
else
metalbn = -(-realbn - bn + NIADDR - i);
/*
* At each iteration, off is the offset into the bap array which is
* an array of disk addresses at the current level of indirection.
* The logical block number and the offset in that block are stored
* into the argument array.
*/
ap->in_lbn = metalbn;
ap->in_off = off = NIADDR - i;
ap++;
for (++numlevels; i <= NIADDR; i++) {
/* If searching for a meta-data block, quit when found. */
if (metalbn == realbn)
break;
lbc -= lognindir;
blockcnt = (int64_t)1 << lbc;
off = (bn >> lbc) & (NINDIR(ip->i_fs) - 1);
++numlevels;
ap->in_lbn = metalbn;
ap->in_off = off;
++ap;
metalbn -= -1 + (off << lbc);
}
if (nump)
*nump = numlevels;
return (0);
}
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