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. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)ffs_subr.c 8.5 (Berkeley) 3/21/95 34 * $FreeBSD: src/sys/ufs/ffs/ffs_subr.c,v 1.25 1999/12/29 04:55:04 peter Exp $ 35 */ 36 37 #include <sys/param.h> 38 39 #ifndef _KERNEL 40 #include "dinode.h" 41 #include "fs.h" 42 extern void panic(const char *, ...); 43 #else 44 #include "opt_ddb.h" 45 46 #include <sys/systm.h> 47 #include <sys/lock.h> 48 #include <sys/vnode.h> 49 #include <sys/buf.h> 50 #include <sys/ucred.h> 51 #include <sys/mount.h> 52 53 #include <sys/buf2.h> 54 55 #include "quota.h" 56 #include "inode.h" 57 #include "fs.h" 58 #include "ffs_extern.h" 59 60 /* 61 * Return buffer with the contents of block "offset" from the beginning of 62 * vnode "vp". If "res" is non-zero, fill it in with a pointer to the 63 * remaining space in the vnode. 64 */ 65 int 66 ffs_blkatoff(struct vnode *vp, off_t uoffset, char **res, struct buf **bpp) 67 { 68 struct inode *ip; 69 struct fs *fs; 70 struct buf *bp; 71 ufs_daddr_t lbn; 72 int bsize, error; 73 74 ip = VTOI(vp); 75 fs = ip->i_fs; 76 lbn = lblkno(fs, uoffset); 77 bsize = blksize(fs, ip, lbn); 78 79 *bpp = NULL; 80 error = bread(vp, lblktodoff(fs, lbn), bsize, &bp); 81 if (error) { 82 brelse(bp); 83 return (error); 84 } 85 if (res) 86 *res = (char *)bp->b_data + blkoff(fs, uoffset); 87 *bpp = bp; 88 return (0); 89 } 90 91 /* 92 * Return buffer with the contents of block "offset" from the beginning of 93 * vnode "vp". If "res" is non-zero, fill it in with a pointer to the 94 * remaining space in the vnode. 95 * 96 * This version includes a read-ahead optimization. 97 */ 98 int 99 ffs_blkatoff_ra(struct vnode *vp, off_t uoffset, char **res, struct buf **bpp, 100 int seqcount) 101 { 102 struct inode *ip; 103 struct fs *fs; 104 struct buf *bp; 105 ufs_daddr_t lbn; 106 ufs_daddr_t nextlbn; 107 off_t base_loffset; 108 off_t next_loffset; 109 int bsize, error; 110 int nextbsize; 111 112 ip = VTOI(vp); 113 fs = ip->i_fs; 114 lbn = lblkno(fs, uoffset); 115 base_loffset = lblktodoff(fs, lbn); 116 bsize = blksize(fs, ip, lbn); 117 118 nextlbn = lbn + 1; 119 next_loffset = lblktodoff(fs, nextlbn); 120 121 122 *bpp = NULL; 123 124 if (next_loffset >= ip->i_size) { 125 /* 126 * Do not do readahead if this is the last block, 127 * bsize might represent a fragment. 128 */ 129 error = bread(vp, base_loffset, bsize, &bp); 130 } else if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERR) == 0) { 131 /* 132 * Try to cluster if we allowed to. 133 */ 134 error = cluster_read(vp, (off_t)ip->i_size, 135 base_loffset, bsize, 136 bsize, seqcount * BKVASIZE, &bp); 137 } else if (seqcount > 1) { 138 /* 139 * Faked read ahead 140 */ 141 nextbsize = blksize(fs, ip, nextlbn); 142 error = breadn(vp, base_loffset, bsize, 143 &next_loffset, &nextbsize, 1, &bp); 144 } else { 145 /* 146 * Failing all of the above, just read what the 147 * user asked for. Interestingly, the same as 148 * the first option above. 149 */ 150 error = bread(vp, base_loffset, bsize, &bp); 151 } 152 if (error) { 153 brelse(bp); 154 return (error); 155 } 156 if (res) 157 *res = (char *)bp->b_data + (int)(uoffset - base_loffset); 158 *bpp = bp; 159 return (0); 160 } 161 162 #endif 163 164 /* 165 * Update the frsum fields to reflect addition or deletion 166 * of some frags. 167 */ 168 void 169 ffs_fragacct(struct fs *fs, int fragmap, int32_t fraglist[], int cnt) 170 { 171 int inblk; 172 int field, subfield; 173 int siz, pos; 174 175 /* 176 * inblk represents a bitmap of fragment sizes which may be 177 * contained in the data 'fragmap'. e.g. if a fragment of size 178 * 1 is available, bit 0 would be set. inblk is shifted left 179 * by one so we do not have to calculate (1 << (siz - 1)). 180 * 181 * fragment represents the data pattern we are trying to decipher, 182 * we shift it left by one to align it with the 'around' and 'inside' 183 * masks. 184 * 185 * around represents the bits around the subfield and is a mask. 186 * inside represents what we must match within the mask, it is 187 * basically the mask with the first and last bit set to 0, allowing 188 * us to represent a whole fragment. 189 * 190 * When we find a match we bump our position by the size of the 191 * matching fragment, then bump the position again: 192 * 193 * 010101010 fragmap (shifted left by 1) 194 * 111 around mask 195 * 010 inside mask 196 * 111 (shifted by siz) 197 * 010 198 * 111 (shifted again) 199 * 010 200 */ 201 inblk = (int)(fragtbl[fs->fs_frag][fragmap]) << 1; 202 fragmap <<= 1; 203 for (siz = 1; siz < fs->fs_frag; siz++) { 204 if ((inblk & (1 << (siz + (fs->fs_frag % NBBY)))) == 0) 205 continue; 206 field = around[siz]; 207 subfield = inside[siz]; 208 for (pos = siz; pos <= fs->fs_frag; pos++) { 209 if ((fragmap & field) == subfield) { 210 fraglist[siz] += cnt; 211 pos += siz; 212 field <<= siz; 213 subfield <<= siz; 214 } 215 field <<= 1; 216 subfield <<= 1; 217 } 218 } 219 } 220 221 /* 222 * block operations 223 * 224 * check if a block is available 225 */ 226 int 227 ffs_isblock(struct fs *fs, unsigned char *cp, ufs_daddr_t h) 228 { 229 unsigned char mask; 230 231 switch ((int)fs->fs_frag) { 232 case 8: 233 return (cp[h] == 0xff); 234 case 4: 235 mask = 0x0f << ((h & 0x1) << 2); 236 return ((cp[h >> 1] & mask) == mask); 237 case 2: 238 mask = 0x03 << ((h & 0x3) << 1); 239 return ((cp[h >> 2] & mask) == mask); 240 case 1: 241 mask = 0x01 << (h & 0x7); 242 return ((cp[h >> 3] & mask) == mask); 243 default: 244 panic("ffs_isblock"); 245 } 246 } 247 248 /* 249 * check if a block is free 250 */ 251 int 252 ffs_isfreeblock(struct fs *fs, unsigned char *cp, ufs_daddr_t h) 253 { 254 switch ((int)fs->fs_frag) { 255 case 8: 256 return (cp[h] == 0); 257 case 4: 258 return ((cp[h >> 1] & (0x0f << ((h & 0x1) << 2))) == 0); 259 case 2: 260 return ((cp[h >> 2] & (0x03 << ((h & 0x3) << 1))) == 0); 261 case 1: 262 return ((cp[h >> 3] & (0x01 << (h & 0x7))) == 0); 263 default: 264 panic("ffs_isfreeblock"); 265 } 266 } 267 268 /* 269 * take a block out of the map 270 */ 271 void 272 ffs_clrblock(struct fs *fs, u_char *cp, ufs_daddr_t h) 273 { 274 switch ((int)fs->fs_frag) { 275 case 8: 276 cp[h] = 0; 277 return; 278 case 4: 279 cp[h >> 1] &= ~(0x0f << ((h & 0x1) << 2)); 280 return; 281 case 2: 282 cp[h >> 2] &= ~(0x03 << ((h & 0x3) << 1)); 283 return; 284 case 1: 285 cp[h >> 3] &= ~(0x01 << (h & 0x7)); 286 return; 287 default: 288 panic("ffs_clrblock"); 289 } 290 } 291 292 /* 293 * put a block into the map 294 */ 295 void 296 ffs_setblock(struct fs *fs, unsigned char *cp, ufs_daddr_t h) 297 { 298 switch ((int)fs->fs_frag) { 299 case 8: 300 cp[h] = 0xff; 301 return; 302 case 4: 303 cp[h >> 1] |= (0x0f << ((h & 0x1) << 2)); 304 return; 305 case 2: 306 cp[h >> 2] |= (0x03 << ((h & 0x3) << 1)); 307 return; 308 case 1: 309 cp[h >> 3] |= (0x01 << (h & 0x7)); 310 return; 311 default: 312 panic("ffs_setblock"); 313 } 314 } 315