usr.sbin/makefs/ffs/ufs_bmap.c

   1 /*      $NetBSD: ufs_bmap.c,v 1.15 2005/06/07 13:54:55 he Exp $ */
   2 /* From: NetBSD: ufs_bmap.c,v 1.14 2001/11/08 05:00:51 chs Exp */
   3
   4 /*
   5  * Copyright (c) 1989, 1991, 1993
   6  *      The Regents of the University of California.  All rights reserved.
   7  * (c) UNIX System Laboratories, Inc.
   8  * All or some portions of this file are derived from material licensed
   9  * to the University of California by American Telephone and Telegraph
  10  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
  11  * the permission of UNIX System Laboratories, Inc.
  12  *
  13  * Redistribution and use in source and binary forms, with or without
  14  * modification, are permitted provided that the following conditions
  15  * are met:
  16  * 1. Redistributions of source code must retain the above copyright
  17  *    notice, this list of conditions and the following disclaimer.
  18  * 2. Redistributions in binary form must reproduce the above copyright
  19  *    notice, this list of conditions and the following disclaimer in the
  20  *    documentation and/or other materials provided with the distribution.
  21  * 3. Neither the name of the University nor the names of its contributors
  22  *    may be used to endorse or promote products derived from this software
  23  *    without specific prior written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  35  * SUCH DAMAGE.
  36  *
  37  *      @(#)ufs_bmap.c  8.8 (Berkeley) 8/11/95
  38  */
  39
  40 #if HAVE_NBTOOL_CONFIG_H
  41 #include "nbtool_config.h"
  42 #endif
  43
  44 #include <sys/cdefs.h>
  45 #if defined(__RCSID) && !defined(__lint)
  46 __RCSID("$NetBSD: ufs_bmap.c,v 1.15 2005/06/07 13:54:55 he Exp $");
  47 #endif  /* !__lint */
  48
  49 #include <sys/param.h>
  50 #include <sys/time.h>
  51
  52 #include <assert.h>
  53 #include <errno.h>
  54 #include <strings.h>
  55
  56 #include "makefs.h"
  57
  58 #include <ufs/ufs/dinode.h>
  59 #include <ufs/ufs/ufs_bswap.h>
  60 #include <ufs/ffs/fs.h>
  61
  62 #include "ffs/ufs_inode.h"
  63 #include "ffs/ffs_extern.h"
  64
  65 /*
  66  * Create an array of logical block number/offset pairs which represent the
  67  * path of indirect blocks required to access a data block.  The first "pair"
  68  * contains the logical block number of the appropriate single, double or
  69  * triple indirect block and the offset into the inode indirect block array.
  70  * Note, the logical block number of the inode single/double/triple indirect
  71  * block appears twice in the array, once with the offset into the i_ffs_ib and
  72  * once with the offset into the page itself.
  73  */
  74 int
  75 ufs_getlbns(struct inode *ip, daddr_t bn, struct indir *ap, int *nump)
  76 {
  77         daddr_t metalbn, realbn;
  78         int64_t blockcnt;
  79         int lbc;
  80         int i, numlevels, off;
  81         u_long lognindir;
  82
  83         lognindir = ffs(NINDIR(ip->i_fs)) - 1;
  84         if (nump)
  85                 *nump = 0;
  86         numlevels = 0;
  87         realbn = bn;
  88         if ((long)bn < 0)
  89                 bn = -(long)bn;
  90
  91         assert (bn >= NDADDR);
  92
  93         /*
  94          * Determine the number of levels of indirection.  After this loop
  95          * is done, blockcnt indicates the number of data blocks possible
  96          * at the given level of indirection, and NIADDR - i is the number
  97          * of levels of indirection needed to locate the requested block.
  98          */
  99
 100         bn -= NDADDR;
 101         for (lbc = 0, i = NIADDR;; i--, bn -= blockcnt) {
 102                 if (i == 0)
 103                         return (EFBIG);
 104
 105                 lbc += lognindir;
 106                 blockcnt = (int64_t)1 << lbc;
 107
 108                 if (bn < blockcnt)
 109                         break;
 110         }
 111
 112         /* Calculate the address of the first meta-block. */
 113         metalbn = -((realbn >= 0 ? realbn : -realbn) - bn + NIADDR - i);
 114
 115         /*
 116          * At each iteration, off is the offset into the bap array which is
 117          * an array of disk addresses at the current level of indirection.
 118          * The logical block number and the offset in that block are stored
 119          * into the argument array.
 120          */
 121         ap->in_lbn = metalbn;
 122         ap->in_off = off = NIADDR - i;
 123         ap->in_exists = 0;
 124         ap++;
 125         for (++numlevels; i <= NIADDR; i++) {
 126                 /* If searching for a meta-data block, quit when found. */
 127                 if (metalbn == realbn)
 128                         break;
 129
 130                 lbc -= lognindir;
 131                 blockcnt = (int64_t)1 << lbc;
 132                 off = (bn >> lbc) & (NINDIR(ip->i_fs) - 1);
 133
 134                 ++numlevels;
 135                 ap->in_lbn = metalbn;
 136                 ap->in_off = off;
 137                 ap->in_exists = 0;
 138                 ++ap;
 139
 140                 metalbn -= -1 + (off << lbc);
 141         }
 142         if (nump)
 143                 *nump = numlevels;
 144         return (0);
 145 }