nblk.c revision 5c51f1241dbbdf2656d0e10011981411ed0c9673
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2008 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/* All Rights Reserved */
#include <sys/types.h>
#include <sys/param.h>
#include <sys/sysmacros.h>
/*
* This should not be a constant, but for ufs it is 12, not 10 like for s5.
*/
#define DIRECT 12 /* Number of logical blocks before indirection */
fsblkcnt_t
nblk(fsblkcnt_t size, ulong_t bsize, ulong_t frsize)
{
fsblkcnt_t tot, count, count1, d_indirect, t_indirect, ind;
fsblkcnt_t frags = 0;
if (size == 0 || bsize == 0)
return (1);
/*
* Need to keep track of indirect blocks.
*/
ind = howmany(bsize, sizeof (daddr_t));
d_indirect = ind + DIRECT; /* double indirection */
t_indirect = ind * (ind + 1) + DIRECT; /* triple indirection */
tot = howmany(size, bsize);
if (tot > t_indirect) {
count1 = (tot - ind * ind - (DIRECT + 1)) / ind;
count = count1 + count1 / ind + ind + 3;
} else if (tot > d_indirect) {
count = (tot - (DIRECT + 1)) / ind + 2;
} else if (tot > DIRECT) {
count = 1;
} else {
count = 0;
frags = (frsize > 0) ?
roundup(size, frsize) :
roundup(size, bsize);
}
/* Accounting for the indirect blocks, the total becomes */
tot += count;
/*
* calculate number of 512 byte blocks, for frag or full block cases.
*/
if (!frags)
tot *= howmany(bsize, DEV_BSIZE);
else
tot = howmany(frags, DEV_BSIZE);
return (tot);
}