| 1 |  |  | /*	$OpenBSD: ffs_subr.c,v 1.4 2016/10/22 19:43:50 natano Exp $	*/ | 
    
    | 2 |  |  | /*	$NetBSD: ffs_subr.c,v 1.49 2016/05/07 11:59:08 maxv Exp $	*/ | 
    
    | 3 |  |  |  | 
    
    | 4 |  |  | /* | 
    
    | 5 |  |  |  * Copyright (c) 1982, 1986, 1989, 1993 | 
    
    | 6 |  |  |  *	The Regents of the University of California.  All rights reserved. | 
    
    | 7 |  |  |  * | 
    
    | 8 |  |  |  * Redistribution and use in source and binary forms, with or without | 
    
    | 9 |  |  |  * modification, are permitted provided that the following conditions | 
    
    | 10 |  |  |  * are met: | 
    
    | 11 |  |  |  * 1. Redistributions of source code must retain the above copyright | 
    
    | 12 |  |  |  *    notice, this list of conditions and the following disclaimer. | 
    
    | 13 |  |  |  * 2. Redistributions in binary form must reproduce the above copyright | 
    
    | 14 |  |  |  *    notice, this list of conditions and the following disclaimer in the | 
    
    | 15 |  |  |  *    documentation and/or other materials provided with the distribution. | 
    
    | 16 |  |  |  * 3. Neither the name of the University nor the names of its contributors | 
    
    | 17 |  |  |  *    may be used to endorse or promote products derived from this software | 
    
    | 18 |  |  |  *    without specific prior written permission. | 
    
    | 19 |  |  |  * | 
    
    | 20 |  |  |  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | 
    
    | 21 |  |  |  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | 
    
    | 22 |  |  |  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | 
    
    | 23 |  |  |  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | 
    
    | 24 |  |  |  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | 
    
    | 25 |  |  |  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | 
    
    | 26 |  |  |  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | 
    
    | 27 |  |  |  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | 
    
    | 28 |  |  |  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | 
    
    | 29 |  |  |  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | 
    
    | 30 |  |  |  * SUCH DAMAGE. | 
    
    | 31 |  |  |  * | 
    
    | 32 |  |  |  *	@(#)ffs_subr.c	8.5 (Berkeley) 3/21/95 | 
    
    | 33 |  |  |  */ | 
    
    | 34 |  |  |  | 
    
    | 35 |  |  | #include <sys/param.h> | 
    
    | 36 |  |  |  | 
    
    | 37 |  |  | #include <ufs/ufs/dinode.h> | 
    
    | 38 |  |  | #include <ufs/ffs/fs.h> | 
    
    | 39 |  |  |  | 
    
    | 40 |  |  | #include <err.h> | 
    
    | 41 |  |  |  | 
    
    | 42 |  |  | #include "ffs/ffs_extern.h" | 
    
    | 43 |  |  |  | 
    
    | 44 |  |  |  | 
    
    | 45 |  |  | /* | 
    
    | 46 |  |  |  * block operations | 
    
    | 47 |  |  |  * | 
    
    | 48 |  |  |  * check if a block is available | 
    
    | 49 |  |  |  *  returns true if all the correponding bits in the free map are 1 | 
    
    | 50 |  |  |  *  returns false if any corresponding bit in the free map is 0 | 
    
    | 51 |  |  |  */ | 
    
    | 52 |  |  | int | 
    
    | 53 |  |  | ffs_isblock(struct fs *fs, u_char *cp, int32_t h) | 
    
    | 54 |  |  | { | 
    
    | 55 |  |  | 	u_char mask; | 
    
    | 56 |  |  |  | 
    
    | 57 |  |  | 	switch ((int)fs->fs_fragshift) { | 
    
    | 58 |  |  | 	case 3: | 
    
    | 59 |  |  | 		return (cp[h] == 0xff); | 
    
    | 60 |  |  | 	case 2: | 
    
    | 61 |  |  | 		mask = 0x0f << ((h & 0x1) << 2); | 
    
    | 62 |  |  | 		return ((cp[h >> 1] & mask) == mask); | 
    
    | 63 |  |  | 	case 1: | 
    
    | 64 |  |  | 		mask = 0x03 << ((h & 0x3) << 1); | 
    
    | 65 |  |  | 		return ((cp[h >> 2] & mask) == mask); | 
    
    | 66 |  |  | 	case 0: | 
    
    | 67 |  |  | 		mask = 0x01 << (h & 0x7); | 
    
    | 68 |  |  | 		return ((cp[h >> 3] & mask) == mask); | 
    
    | 69 |  |  | 	default: | 
    
    | 70 |  |  | 		errx(1, "ffs_isblock: unknown fs_fragshift %d", | 
    
    | 71 |  |  | 		    (int)fs->fs_fragshift); | 
    
    | 72 |  |  | 	} | 
    
    | 73 |  |  | } | 
    
    | 74 |  |  |  | 
    
    | 75 |  |  | /* | 
    
    | 76 |  |  |  * take a block out of the map | 
    
    | 77 |  |  |  */ | 
    
    | 78 |  |  | void | 
    
    | 79 |  |  | ffs_clrblock(struct fs *fs, u_char *cp, int32_t h) | 
    
    | 80 |  |  | { | 
    
    | 81 |  |  |  | 
    
    | 82 |  |  | 	switch ((int)fs->fs_fragshift) { | 
    
    | 83 |  |  | 	case 3: | 
    
    | 84 |  |  | 		cp[h] = 0; | 
    
    | 85 |  |  | 		return; | 
    
    | 86 |  |  | 	case 2: | 
    
    | 87 |  |  | 		cp[h >> 1] &= ~(0x0f << ((h & 0x1) << 2)); | 
    
    | 88 |  |  | 		return; | 
    
    | 89 |  |  | 	case 1: | 
    
    | 90 |  |  | 		cp[h >> 2] &= ~(0x03 << ((h & 0x3) << 1)); | 
    
    | 91 |  |  | 		return; | 
    
    | 92 |  |  | 	case 0: | 
    
    | 93 |  |  | 		cp[h >> 3] &= ~(0x01 << (h & 0x7)); | 
    
    | 94 |  |  | 		return; | 
    
    | 95 |  |  | 	default: | 
    
    | 96 |  |  | 		errx(1, "ffs_clrblock: unknown fs_fragshift %d", | 
    
    | 97 |  |  | 		    (int)fs->fs_fragshift); | 
    
    | 98 |  |  | 	} | 
    
    | 99 |  |  | } | 
    
    | 100 |  |  |  | 
    
    | 101 |  |  | /* | 
    
    | 102 |  |  |  * put a block into the map | 
    
    | 103 |  |  |  */ | 
    
    | 104 |  |  | void | 
    
    | 105 |  |  | ffs_setblock(struct fs *fs, u_char *cp, int32_t h) | 
    
    | 106 |  |  | { | 
    
    | 107 |  |  |  | 
    
    | 108 |  |  | 	switch ((int)fs->fs_fragshift) { | 
    
    | 109 |  |  | 	case 3: | 
    
    | 110 |  |  | 		cp[h] = 0xff; | 
    
    | 111 |  |  | 		return; | 
    
    | 112 |  |  | 	case 2: | 
    
    | 113 |  |  | 		cp[h >> 1] |= (0x0f << ((h & 0x1) << 2)); | 
    
    | 114 |  |  | 		return; | 
    
    | 115 |  |  | 	case 1: | 
    
    | 116 |  |  | 		cp[h >> 2] |= (0x03 << ((h & 0x3) << 1)); | 
    
    | 117 |  |  | 		return; | 
    
    | 118 |  |  | 	case 0: | 
    
    | 119 |  |  | 		cp[h >> 3] |= (0x01 << (h & 0x7)); | 
    
    | 120 |  |  | 		return; | 
    
    | 121 |  |  | 	default: | 
    
    | 122 |  |  | 		errx(1, "ffs_setblock: unknown fs_fragshift %d", | 
    
    | 123 |  |  | 		    (int)fs->fs_fragshift); | 
    
    | 124 |  |  | 	} | 
    
    | 125 |  |  | } | 
    
    | 126 |  |  |  | 
    
    | 127 |  |  | /* | 
    
    | 128 |  |  |  * Update the cluster map because of an allocation or free. | 
    
    | 129 |  |  |  * | 
    
    | 130 |  |  |  * Cnt == 1 means free; cnt == -1 means allocating. | 
    
    | 131 |  |  |  */ | 
    
    | 132 |  |  | void | 
    
    | 133 |  |  | ffs_clusteracct(struct fs *fs, struct cg *cgp, int32_t blkno, int cnt) | 
    
    | 134 |  |  | { | 
    
    | 135 |  |  | 	int32_t *sump; | 
    
    | 136 |  |  | 	int32_t *lp; | 
    
    | 137 |  |  | 	u_char *freemapp, *mapp; | 
    
    | 138 |  |  | 	int i, start, end, forw, back, map, bit; | 
    
    | 139 |  |  |  | 
    
    | 140 |  |  | 	/* KASSERT(mutex_owned(&ump->um_lock)); */ | 
    
    | 141 |  |  |  | 
    
    | 142 |  |  | 	if (fs->fs_contigsumsize <= 0) | 
    
    | 143 |  |  | 		return; | 
    
    | 144 |  |  | 	freemapp = cg_clustersfree(cgp); | 
    
    | 145 |  |  | 	sump = cg_clustersum(cgp); | 
    
    | 146 |  |  | 	/* | 
    
    | 147 |  |  | 	 * Allocate or clear the actual block. | 
    
    | 148 |  |  | 	 */ | 
    
    | 149 |  |  | 	if (cnt > 0) | 
    
    | 150 |  |  | 		setbit(freemapp, blkno); | 
    
    | 151 |  |  | 	else | 
    
    | 152 |  |  | 		clrbit(freemapp, blkno); | 
    
    | 153 |  |  | 	/* | 
    
    | 154 |  |  | 	 * Find the size of the cluster going forward. | 
    
    | 155 |  |  | 	 */ | 
    
    | 156 |  |  | 	start = blkno + 1; | 
    
    | 157 |  |  | 	end = start + fs->fs_contigsumsize; | 
    
    | 158 |  |  | 	if ((uint32_t)end >= cgp->cg_nclusterblks) | 
    
    | 159 |  |  | 		end = cgp->cg_nclusterblks; | 
    
    | 160 |  |  | 	mapp = &freemapp[start / NBBY]; | 
    
    | 161 |  |  | 	map = *mapp++; | 
    
    | 162 |  |  | 	bit = 1 << (start % NBBY); | 
    
    | 163 |  |  | 	for (i = start; i < end; i++) { | 
    
    | 164 |  |  | 		if ((map & bit) == 0) | 
    
    | 165 |  |  | 			break; | 
    
    | 166 |  |  | 		if ((i & (NBBY - 1)) != (NBBY - 1)) { | 
    
    | 167 |  |  | 			bit <<= 1; | 
    
    | 168 |  |  | 		} else { | 
    
    | 169 |  |  | 			map = *mapp++; | 
    
    | 170 |  |  | 			bit = 1; | 
    
    | 171 |  |  | 		} | 
    
    | 172 |  |  | 	} | 
    
    | 173 |  |  | 	forw = i - start; | 
    
    | 174 |  |  | 	/* | 
    
    | 175 |  |  | 	 * Find the size of the cluster going backward. | 
    
    | 176 |  |  | 	 */ | 
    
    | 177 |  |  | 	start = blkno - 1; | 
    
    | 178 |  |  | 	end = start - fs->fs_contigsumsize; | 
    
    | 179 |  |  | 	if (end < 0) | 
    
    | 180 |  |  | 		end = -1; | 
    
    | 181 |  |  | 	mapp = &freemapp[start / NBBY]; | 
    
    | 182 |  |  | 	map = *mapp--; | 
    
    | 183 |  |  | 	bit = 1 << (start % NBBY); | 
    
    | 184 |  |  | 	for (i = start; i > end; i--) { | 
    
    | 185 |  |  | 		if ((map & bit) == 0) | 
    
    | 186 |  |  | 			break; | 
    
    | 187 |  |  | 		if ((i & (NBBY - 1)) != 0) { | 
    
    | 188 |  |  | 			bit >>= 1; | 
    
    | 189 |  |  | 		} else { | 
    
    | 190 |  |  | 			map = *mapp--; | 
    
    | 191 |  |  | 			bit = 1 << (NBBY - 1); | 
    
    | 192 |  |  | 		} | 
    
    | 193 |  |  | 	} | 
    
    | 194 |  |  | 	back = start - i; | 
    
    | 195 |  |  | 	/* | 
    
    | 196 |  |  | 	 * Account for old cluster and the possibly new forward and | 
    
    | 197 |  |  | 	 * back clusters. | 
    
    | 198 |  |  | 	 */ | 
    
    | 199 |  |  | 	i = back + forw + 1; | 
    
    | 200 |  |  | 	if (i > fs->fs_contigsumsize) | 
    
    | 201 |  |  | 		i = fs->fs_contigsumsize; | 
    
    | 202 |  |  | 	sump[i] += cnt; | 
    
    | 203 |  |  | 	if (back > 0) | 
    
    | 204 |  |  | 		sump[back] -= cnt; | 
    
    | 205 |  |  | 	if (forw > 0) | 
    
    | 206 |  |  | 		sump[forw] -= cnt; | 
    
    | 207 |  |  |  | 
    
    | 208 |  |  | 	/* | 
    
    | 209 |  |  | 	 * Update cluster summary information. | 
    
    | 210 |  |  | 	 */ | 
    
    | 211 |  |  | 	lp = &sump[fs->fs_contigsumsize]; | 
    
    | 212 |  |  | 	for (i = fs->fs_contigsumsize; i > 0; i--) | 
    
    | 213 |  |  | 		if (*lp-- > 0) | 
    
    | 214 |  |  | 			break; | 
    
    | 215 |  |  | } |