ffs_subr.c revision 285830 
1/*	$NetBSD: ffs_subr.c,v 1.32 2003/12/30 12:33:24 pk Exp $	*/
2
3/*
4 * Copyright (c) 1982, 1986, 1989, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 *
31 *	@(#)ffs_subr.c	8.5 (Berkeley) 3/21/95
32 */
33
34#include <sys/cdefs.h>
35__FBSDID("$FreeBSD: releng/10.2/usr.sbin/makefs/ffs/ffs_subr.c 228990 2011-12-30 10:58:14Z uqs $");
36
37#include <sys/param.h>
38
39#include <ufs/ufs/dinode.h>
40#include <ufs/ffs/fs.h>
41#include "ffs/ffs_extern.h"
42#include "ffs/ufs_bswap.h"
43
44/*
45 * Update the frsum fields to reflect addition or deletion
46 * of some frags.
47 */
48void
49ffs_fragacct_swap(struct fs *fs, int fragmap, int32_t fraglist[], int cnt, int needswap)
50{
51	int inblk;
52	int field, subfield;
53	int siz, pos;
54
55	inblk = (int)(fragtbl[fs->fs_frag][fragmap]) << 1;
56	fragmap <<= 1;
57	for (siz = 1; siz < fs->fs_frag; siz++) {
58		if ((inblk & (1 << (siz + (fs->fs_frag & (NBBY - 1))))) == 0)
59			continue;
60		field = around[siz];
61		subfield = inside[siz];
62		for (pos = siz; pos <= fs->fs_frag; pos++) {
63			if ((fragmap & field) == subfield) {
64				fraglist[siz] = ufs_rw32(
65				    ufs_rw32(fraglist[siz], needswap) + cnt,
66				    needswap);
67				pos += siz;
68				field <<= siz;
69				subfield <<= siz;
70			}
71			field <<= 1;
72			subfield <<= 1;
73		}
74	}
75}
76
77/*
78 * block operations
79 *
80 * check if a block is available
81 *  returns true if all the corresponding bits in the free map are 1
82 *  returns false if any corresponding bit in the free map is 0
83 */
84int
85ffs_isblock(fs, cp, h)
86	struct fs *fs;
87	u_char *cp;
88	int32_t h;
89{
90	u_char mask;
91
92	switch ((int)fs->fs_fragshift) {
93	case 3:
94		return (cp[h] == 0xff);
95	case 2:
96		mask = 0x0f << ((h & 0x1) << 2);
97		return ((cp[h >> 1] & mask) == mask);
98	case 1:
99		mask = 0x03 << ((h & 0x3) << 1);
100		return ((cp[h >> 2] & mask) == mask);
101	case 0:
102		mask = 0x01 << (h & 0x7);
103		return ((cp[h >> 3] & mask) == mask);
104	default:
105		panic("ffs_isblock: unknown fs_fragshift %d",
106		    (int)fs->fs_fragshift);
107	}
108}
109
110/*
111 * check if a block is completely allocated
112 *  returns true if all the corresponding bits in the free map are 0
113 *  returns false if any corresponding bit in the free map is 1
114 */
115int
116ffs_isfreeblock(fs, cp, h)
117	struct fs *fs;
118	u_char *cp;
119	int32_t h;
120{
121
122	switch ((int)fs->fs_fragshift) {
123	case 3:
124		return (cp[h] == 0);
125	case 2:
126		return ((cp[h >> 1] & (0x0f << ((h & 0x1) << 2))) == 0);
127	case 1:
128		return ((cp[h >> 2] & (0x03 << ((h & 0x3) << 1))) == 0);
129	case 0:
130		return ((cp[h >> 3] & (0x01 << (h & 0x7))) == 0);
131	default:
132		panic("ffs_isfreeblock: unknown fs_fragshift %d",
133		    (int)fs->fs_fragshift);
134	}
135}
136
137/*
138 * take a block out of the map
139 */
140void
141ffs_clrblock(fs, cp, h)
142	struct fs *fs;
143	u_char *cp;
144	int32_t h;
145{
146
147	switch ((int)fs->fs_fragshift) {
148	case 3:
149		cp[h] = 0;
150		return;
151	case 2:
152		cp[h >> 1] &= ~(0x0f << ((h & 0x1) << 2));
153		return;
154	case 1:
155		cp[h >> 2] &= ~(0x03 << ((h & 0x3) << 1));
156		return;
157	case 0:
158		cp[h >> 3] &= ~(0x01 << (h & 0x7));
159		return;
160	default:
161		panic("ffs_clrblock: unknown fs_fragshift %d",
162		    (int)fs->fs_fragshift);
163	}
164}
165
166/*
167 * put a block into the map
168 */
169void
170ffs_setblock(fs, cp, h)
171	struct fs *fs;
172	u_char *cp;
173	int32_t h;
174{
175
176	switch ((int)fs->fs_fragshift) {
177	case 3:
178		cp[h] = 0xff;
179		return;
180	case 2:
181		cp[h >> 1] |= (0x0f << ((h & 0x1) << 2));
182		return;
183	case 1:
184		cp[h >> 2] |= (0x03 << ((h & 0x3) << 1));
185		return;
186	case 0:
187		cp[h >> 3] |= (0x01 << (h & 0x7));
188		return;
189	default:
190		panic("ffs_setblock: unknown fs_fragshift %d",
191		    (int)fs->fs_fragshift);
192	}
193}
194