1 /* 2 * Copyright (c) 1982, 1986, 1989, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)ffs_subr.c 8.5 (Berkeley) 3/21/95 30 * $FreeBSD: src/sys/ufs/ffs/ffs_subr.c,v 1.25 1999/12/29 04:55:04 peter Exp $ 31 */ 32 33 #include <sys/param.h> 34 35 #ifndef _KERNEL 36 #include "dinode.h" 37 #include "fs.h" 38 extern void panic(const char *, ...) __printflike(1, 2) __dead2; 39 #else 40 #include <sys/systm.h> 41 #include <sys/lock.h> 42 #include <sys/vnode.h> 43 #include <sys/buf.h> 44 #include <sys/ucred.h> 45 #include <sys/mount.h> 46 47 #include <sys/buf2.h> 48 49 #include "quota.h" 50 #include "inode.h" 51 #include "fs.h" 52 #include "ffs_extern.h" 53 54 /* 55 * Return buffer with the contents of block "offset" from the beginning of 56 * vnode "vp". If "res" is non-zero, fill it in with a pointer to the 57 * remaining space in the vnode. 58 */ 59 int 60 ffs_blkatoff(struct vnode *vp, off_t uoffset, char **res, struct buf **bpp) 61 { 62 struct inode *ip; 63 struct fs *fs; 64 struct buf *bp; 65 ufs_daddr_t lbn; 66 int bsize, error; 67 68 ip = VTOI(vp); 69 fs = ip->i_fs; 70 lbn = lblkno(fs, uoffset); 71 bsize = blksize(fs, ip, lbn); 72 73 *bpp = NULL; 74 error = bread(vp, lblktodoff(fs, lbn), bsize, &bp); 75 if (error) { 76 brelse(bp); 77 return (error); 78 } 79 if (res) 80 *res = (char *)bp->b_data + blkoff(fs, uoffset); 81 *bpp = bp; 82 return (0); 83 } 84 85 /* 86 * Return buffer with the contents of block "offset" from the beginning of 87 * vnode "vp". If "res" is non-zero, fill it in with a pointer to the 88 * remaining space in the vnode. 89 * 90 * This version includes a read-ahead optimization. 91 */ 92 int 93 ffs_blkatoff_ra(struct vnode *vp, off_t uoffset, char **res, struct buf **bpp, 94 int seqcount) 95 { 96 struct inode *ip; 97 struct fs *fs; 98 struct buf *bp; 99 ufs_daddr_t lbn; 100 ufs_daddr_t nextlbn; 101 off_t base_loffset; 102 off_t next_loffset; 103 int bsize, error; 104 int nextbsize; 105 106 ip = VTOI(vp); 107 fs = ip->i_fs; 108 lbn = lblkno(fs, uoffset); 109 base_loffset = lblktodoff(fs, lbn); 110 bsize = blksize(fs, ip, lbn); 111 112 nextlbn = lbn + 1; 113 next_loffset = lblktodoff(fs, nextlbn); 114 115 116 *bpp = NULL; 117 118 if (next_loffset >= ip->i_size) { 119 /* 120 * Do not do readahead if this is the last block, 121 * bsize might represent a fragment. 122 */ 123 error = bread(vp, base_loffset, bsize, &bp); 124 } else if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERR) == 0) { 125 /* 126 * Try to cluster if we allowed to. 127 */ 128 error = cluster_read(vp, (off_t)ip->i_size, 129 base_loffset, bsize, 130 bsize, seqcount * MAXBSIZE, &bp); 131 } else if (seqcount > 1) { 132 /* 133 * Faked read ahead 134 */ 135 nextbsize = blksize(fs, ip, nextlbn); 136 error = breadn(vp, base_loffset, bsize, 137 &next_loffset, &nextbsize, 1, &bp); 138 } else { 139 /* 140 * Failing all of the above, just read what the 141 * user asked for. Interestingly, the same as 142 * the first option above. 143 */ 144 error = bread(vp, base_loffset, bsize, &bp); 145 } 146 if (error) { 147 brelse(bp); 148 return (error); 149 } 150 if (res) 151 *res = (char *)bp->b_data + (int)(uoffset - base_loffset); 152 *bpp = bp; 153 return (0); 154 } 155 156 #endif 157 158 /* 159 * Update the frsum fields to reflect addition or deletion 160 * of some frags. 161 */ 162 void 163 ffs_fragacct(struct fs *fs, int fragmap, int32_t fraglist[], int cnt) 164 { 165 int inblk; 166 int field, subfield; 167 int siz, pos; 168 169 /* 170 * inblk represents a bitmap of fragment sizes which may be 171 * contained in the data 'fragmap'. e.g. if a fragment of size 172 * 1 is available, bit 0 would be set. inblk is shifted left 173 * by one so we do not have to calculate (1 << (siz - 1)). 174 * 175 * fragment represents the data pattern we are trying to decipher, 176 * we shift it left by one to align it with the 'around' and 'inside' 177 * masks. 178 * 179 * around represents the bits around the subfield and is a mask. 180 * inside represents what we must match within the mask, it is 181 * basically the mask with the first and last bit set to 0, allowing 182 * us to represent a whole fragment. 183 * 184 * When we find a match we bump our position by the size of the 185 * matching fragment, then bump the position again: 186 * 187 * 010101010 fragmap (shifted left by 1) 188 * 111 around mask 189 * 010 inside mask 190 * 111 (shifted by siz) 191 * 010 192 * 111 (shifted again) 193 * 010 194 */ 195 inblk = (int)(fragtbl[fs->fs_frag][fragmap]) << 1; 196 fragmap <<= 1; 197 for (siz = 1; siz < fs->fs_frag; siz++) { 198 if ((inblk & (1 << (siz + (fs->fs_frag % NBBY)))) == 0) 199 continue; 200 field = around[siz]; 201 subfield = inside[siz]; 202 for (pos = siz; pos <= fs->fs_frag; pos++) { 203 if ((fragmap & field) == subfield) { 204 fraglist[siz] += cnt; 205 pos += siz; 206 field <<= siz; 207 subfield <<= siz; 208 } 209 field <<= 1; 210 subfield <<= 1; 211 } 212 } 213 } 214 215 /* 216 * block operations 217 * 218 * check if a block is available 219 */ 220 int 221 ffs_isblock(struct fs *fs, unsigned char *cp, ufs_daddr_t h) 222 { 223 unsigned char mask; 224 225 switch ((int)fs->fs_frag) { 226 case 8: 227 return (cp[h] == 0xff); 228 case 4: 229 mask = 0x0f << ((h & 0x1) << 2); 230 return ((cp[h >> 1] & mask) == mask); 231 case 2: 232 mask = 0x03 << ((h & 0x3) << 1); 233 return ((cp[h >> 2] & mask) == mask); 234 case 1: 235 mask = 0x01 << (h & 0x7); 236 return ((cp[h >> 3] & mask) == mask); 237 default: 238 panic("ffs_isblock"); 239 } 240 } 241 242 /* 243 * check if a block is free 244 */ 245 int 246 ffs_isfreeblock(struct fs *fs, unsigned char *cp, ufs_daddr_t h) 247 { 248 switch ((int)fs->fs_frag) { 249 case 8: 250 return (cp[h] == 0); 251 case 4: 252 return ((cp[h >> 1] & (0x0f << ((h & 0x1) << 2))) == 0); 253 case 2: 254 return ((cp[h >> 2] & (0x03 << ((h & 0x3) << 1))) == 0); 255 case 1: 256 return ((cp[h >> 3] & (0x01 << (h & 0x7))) == 0); 257 default: 258 panic("ffs_isfreeblock"); 259 } 260 } 261 262 /* 263 * take a block out of the map 264 */ 265 void 266 ffs_clrblock(struct fs *fs, u_char *cp, ufs_daddr_t h) 267 { 268 switch ((int)fs->fs_frag) { 269 case 8: 270 cp[h] = 0; 271 return; 272 case 4: 273 cp[h >> 1] &= ~(0x0f << ((h & 0x1) << 2)); 274 return; 275 case 2: 276 cp[h >> 2] &= ~(0x03 << ((h & 0x3) << 1)); 277 return; 278 case 1: 279 cp[h >> 3] &= ~(0x01 << (h & 0x7)); 280 return; 281 default: 282 panic("ffs_clrblock"); 283 } 284 } 285 286 /* 287 * put a block into the map 288 */ 289 void 290 ffs_setblock(struct fs *fs, unsigned char *cp, ufs_daddr_t h) 291 { 292 switch ((int)fs->fs_frag) { 293 case 8: 294 cp[h] = 0xff; 295 return; 296 case 4: 297 cp[h >> 1] |= (0x0f << ((h & 0x1) << 2)); 298 return; 299 case 2: 300 cp[h >> 2] |= (0x03 << ((h & 0x3) << 1)); 301 return; 302 case 1: 303 cp[h >> 3] |= (0x01 << (h & 0x7)); 304 return; 305 default: 306 panic("ffs_setblock"); 307 } 308 } 309