usr/src/cmd/svr4pkg/libinst/nblk.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
  28 /* All Rights Reserved */
  29
  30
  31 #include <sys/types.h>
  32 #include <sys/param.h>
  33 #include <sys/sysmacros.h>
  34
  35 /*
  36  * This should not be a constant, but for ufs it is 12, not 10 like for s5.
  37  */
  38 #define DIRECT 12       /* Number of logical blocks before indirection */
  39
  40 fsblkcnt_t
  41 nblk(fsblkcnt_t size, ulong_t bsize, ulong_t frsize)
  42 {
  43         fsblkcnt_t tot, count, count1, d_indirect, t_indirect, ind;
  44         fsblkcnt_t frags = 0;
  45
  46         if (size == 0 || bsize == 0)
  47                 return (1);
  48
  49         /*
  50          * Need to keep track of indirect blocks.
  51          */
  52
  53         ind = howmany(bsize, sizeof (daddr_t));
  54         d_indirect = ind + DIRECT;                      /* double indirection */
  55         t_indirect = ind * (ind + 1) + DIRECT;          /* triple indirection */
  56
  57         tot = howmany(size, bsize);
  58
  59         if (tot > t_indirect) {
  60                 count1 = (tot - ind * ind - (DIRECT + 1)) / ind;
  61                 count = count1 + count1 / ind + ind + 3;
  62         } else if (tot > d_indirect) {
  63                 count = (tot - (DIRECT + 1)) / ind + 2;
  64         } else if (tot > DIRECT) {
  65                 count = 1;
  66         } else {
  67                 count = 0;
  68                 frags = (frsize > 0) ?
  69                     roundup(size, frsize) :
  70                     roundup(size, bsize);
  71         }
  72
  73         /* Accounting for the indirect blocks, the total becomes */
  74         tot += count;
  75
  76         /*
  77          * calculate number of 512 byte blocks, for frag or full block cases.
  78          */
  79         if (!frags)
  80                 tot *= howmany(bsize, DEV_BSIZE);
  81         else
  82                 tot = howmany(frags, DEV_BSIZE);
  83         return (tot);
  84 }