sys/vfs/ufs/ffs_subr.c

   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 }