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/*      $NetBSD: ufs_bmap.c,v 1.16 2005/10/08 03:21:17 chs 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

 */

#if HAVE_NBTOOL_CONFIG_H

#include "nbtool_config.h"

#endif

#include <sys/cdefs.h>

#if defined(__RCSID) && !defined(__lint)

__RCSID("$NetBSD: ufs_bmap.c,v 1.16 2005/10/08 03:21:17 chs Exp $");

#endif  /* !__lint */

#include <sys/param.h>

#include <sys/time.h>

#include <assert.h>

#include <errno.h>

#include <strings.h>

//#include "makefs.h"

#include "common.h"

#include "dinode.h"

#include "ufs_bswap.h"

#include "fs.h"

#include "ufs_inode.h"

#include "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. */

        metalbn = -((realbn >= 0 ? realbn : -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->in_exists = 0;

        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->in_exists = 0;

                ++ap;

                metalbn -= -1 + (off << lbc);

        }

        if (nump)

                *nump = numlevels;

        return (0);

}