sys/gnu/fs/ext2fs/ext2_balloc.c

   1 /*
   2  *  modified for Lites 1.1
   3  *
   4  *  Aug 1995, Godmar Back (gback@cs.utah.edu)
   5  *  University of Utah, Department of Computer Science
   6  */
   7 /*
   8  * Copyright (c) 1982, 1986, 1989, 1993
   9  *      The Regents of the University of California.  All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  * 3. All advertising materials mentioning features or use of this software
  20  *    must display the following acknowledgement:
  21  *      This product includes software developed by the University of
  22  *      California, Berkeley and its contributors.
  23  * 4. Neither the name of the University nor the names of its contributors
  24  *    may be used to endorse or promote products derived from this software
  25  *    without specific prior written permission.
  26  *
  27  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  37  * SUCH DAMAGE.
  38  *
  39  *      @(#)ffs_balloc.c        8.4 (Berkeley) 9/23/93
  40  */
  41
  42 #include <sys/param.h>
  43 #include <sys/systm.h>
  44 #include <sys/buf.h>
  45 #include <sys/lock.h>
  46 #include <sys/ucred.h>
  47 #include <sys/vnode.h>
  48
  49 #include <ufs/ufs/quota.h>
  50 #include <ufs/ufs/inode.h>
  51 #include <ufs/ufs/ufs_extern.h>
  52
  53 #include <gnu/ext2fs/ext2_fs.h>
  54 #include <gnu/ext2fs/ext2_fs_sb.h>
  55 #include <gnu/ext2fs/fs.h>
  56 #include <gnu/ext2fs/ext2_extern.h>
  57
  58 /*
  59  * Balloc defines the structure of file system storage
  60  * by allocating the physical blocks on a device given
  61  * the inode and the logical block number in a file.
  62  */
  63 int
  64 ext2_balloc(ip, bn, size, cred, bpp, flags)
  65         register struct inode *ip;
  66         register daddr_t bn;
  67         int size;
  68         struct ucred *cred;
  69         struct buf **bpp;
  70         int flags;
  71 {
  72         register struct ext2_sb_info *fs;
  73         register daddr_t nb;
  74         struct buf *bp, *nbp;
  75         struct vnode *vp = ITOV(ip);
  76         struct indir indirs[NIADDR + 2];
  77         daddr_t newb, lbn, *bap, pref;
  78         int osize, nsize, num, i, error;
  79 /*
  80 ext2_debug("ext2_balloc called (%d, %d, %d)\n",
  81         ip->i_number, (int)bn, (int)size);
  82 */
  83         *bpp = NULL;
  84         if (bn < 0)
  85                 return (EFBIG);
  86         fs = ip->i_e2fs;
  87         lbn = bn;
  88
  89         /*
  90          * check if this is a sequential block allocation.
  91          * If so, increment next_alloc fields to allow ext2_blkpref
  92          * to make a good guess
  93          */
  94         if (lbn == ip->i_next_alloc_block + 1) {
  95                 ip->i_next_alloc_block++;
  96                 ip->i_next_alloc_goal++;
  97         }
  98
  99         /*
 100          * The first NDADDR blocks are direct blocks
 101          */
 102         if (bn < NDADDR) {
 103                 nb = ip->i_db[bn];
 104                 /* no new block is to be allocated, and no need to expand
 105                    the file */
 106                 if (nb != 0 && ip->i_size >= (bn + 1) * fs->s_blocksize) {
 107                         error = bread(vp, bn, fs->s_blocksize, NOCRED, &bp);
 108                         if (error) {
 109                                 brelse(bp);
 110                                 return (error);
 111                         }
 112                         *bpp = bp;
 113                         return (0);
 114                 }
 115                 if (nb != 0) {
 116                         /*
 117                          * Consider need to reallocate a fragment.
 118                          */
 119                         osize = fragroundup(fs, blkoff(fs, ip->i_size));
 120                         nsize = fragroundup(fs, size);
 121                         if (nsize <= osize) {
 122                                 error = bread(vp, bn, osize, NOCRED, &bp);
 123                                 if (error) {
 124                                         brelse(bp);
 125                                         return (error);
 126                                 }
 127                         } else {
 128                         /* Godmar thinks: this shouldn't happen w/o fragments */
 129                                 printf("nsize %d(%d) > osize %d(%d) nb %d\n",
 130                                         (int)nsize, (int)size, (int)osize,
 131                                         (int)ip->i_size, (int)nb);
 132                                 panic(
 133                                     "ext2_balloc: Something is terribly wrong");
 134 /*
 135  * please note there haven't been any changes from here on -
 136  * FFS seems to work.
 137  */
 138                         }
 139                 } else {
 140                         if (ip->i_size < (bn + 1) * fs->s_blocksize)
 141                                 nsize = fragroundup(fs, size);
 142                         else
 143                                 nsize = fs->s_blocksize;
 144                         error = ext2_alloc(ip, bn,
 145                             ext2_blkpref(ip, bn, (int)bn, &ip->i_db[0], 0),
 146                             nsize, cred, &newb);
 147                         if (error)
 148                                 return (error);
 149                         bp = getblk(vp, bn, nsize, 0, 0);
 150                         bp->b_blkno = fsbtodb(fs, newb);
 151                         if (flags & B_CLRBUF)
 152                                 vfs_bio_clrbuf(bp);
 153                 }
 154                 ip->i_db[bn] = dbtofsb(fs, bp->b_blkno);
 155                 ip->i_flag |= IN_CHANGE | IN_UPDATE;
 156                 *bpp = bp;
 157                 return (0);
 158         }
 159         /*
 160          * Determine the number of levels of indirection.
 161          */
 162         pref = 0;
 163         if ((error = ufs_getlbns(vp, bn, indirs, &num)) != 0)
 164                 return(error);
 165 #if DIAGNOSTIC
 166         if (num < 1)
 167                 panic ("ext2_balloc: ufs_bmaparray returned indirect block");
 168 #endif
 169         /*
 170          * Fetch the first indirect block allocating if necessary.
 171          */
 172         --num;
 173         nb = ip->i_ib[indirs[0].in_off];
 174         if (nb == 0) {
 175 #if 0
 176                 pref = ext2_blkpref(ip, lbn, 0, (daddr_t *)0, 0);
 177 #else
 178                 /* see the comment by ext2_blkpref. What we do here is
 179                    to pretend that it'd be good for a block holding indirect
 180                    pointers to be allocated near its predecessor in terms
 181                    of indirection, or the last direct block.
 182                    We shamelessly exploit the fact that i_ib immediately
 183                    follows i_db.
 184                    Godmar thinks it make sense to allocate i_ib[0] immediately
 185                    after i_db[11], but it's not utterly clear whether this also
 186                    applies to i_ib[1] and i_ib[0]
 187                 */
 188
 189                 pref = ext2_blkpref(ip, lbn, indirs[0].in_off +
 190                                              EXT2_NDIR_BLOCKS, &ip->i_db[0], 0);
 191 #endif
 192                 if ((error = ext2_alloc(ip, lbn, pref, (int)fs->s_blocksize,
 193                     cred, &newb)) != 0)
 194                         return (error);
 195                 nb = newb;
 196                 bp = getblk(vp, indirs[1].in_lbn, fs->s_blocksize, 0, 0);
 197                 bp->b_blkno = fsbtodb(fs, newb);
 198                 vfs_bio_clrbuf(bp);
 199                 /*
 200                  * Write synchronously so that indirect blocks
 201                  * never point at garbage.
 202                  */
 203                 if ((error = bwrite(bp)) != 0) {
 204                         ext2_blkfree(ip, nb, fs->s_blocksize);
 205                         return (error);
 206                 }
 207                 ip->i_ib[indirs[0].in_off] = newb;
 208                 ip->i_flag |= IN_CHANGE | IN_UPDATE;
 209         }
 210         /*
 211          * Fetch through the indirect blocks, allocating as necessary.
 212          */
 213         for (i = 1;;) {
 214                 error = bread(vp,
 215                     indirs[i].in_lbn, (int)fs->s_blocksize, NOCRED, &bp);
 216                 if (error) {
 217                         brelse(bp);
 218                         return (error);
 219                 }
 220                 bap = (daddr_t *)bp->b_data;
 221                 nb = bap[indirs[i].in_off];
 222                 if (i == num)
 223                         break;
 224                 i += 1;
 225                 if (nb != 0) {
 226                         brelse(bp);
 227                         continue;
 228                 }
 229                 if (pref == 0)
 230 #if 1
 231                         /* see the comment above and by ext2_blkpref
 232                          * I think this implements Linux policy, but
 233                          * does it really make sense to allocate to
 234                          * block containing pointers together ?
 235                          * Also, will it ever succeed ?
 236                          */
 237                         pref = ext2_blkpref(ip, lbn, indirs[i].in_off, bap,
 238                                                 bp->b_lblkno);
 239 #else
 240                         pref = ext2_blkpref(ip, lbn, 0, (daddr_t *)0, 0);
 241 #endif
 242                 if ((error =
 243                     ext2_alloc(ip, lbn, pref, (int)fs->s_blocksize, cred, &newb)) != 0) {
 244                         brelse(bp);
 245                         return (error);
 246                 }
 247                 nb = newb;
 248                 nbp = getblk(vp, indirs[i].in_lbn, fs->s_blocksize, 0, 0);
 249                 nbp->b_blkno = fsbtodb(fs, nb);
 250                 vfs_bio_clrbuf(nbp);
 251                 /*
 252                  * Write synchronously so that indirect blocks
 253                  * never point at garbage.
 254                  */
 255                 if ((error = bwrite(nbp)) != 0) {
 256                         ext2_blkfree(ip, nb, fs->s_blocksize);
 257                         brelse(bp);
 258                         return (error);
 259                 }
 260                 bap[indirs[i - 1].in_off] = nb;
 261                 /*
 262                  * If required, write synchronously, otherwise use
 263                  * delayed write.
 264                  */
 265                 if (flags & B_SYNC) {
 266                         bwrite(bp);
 267                 } else {
 268                         bdwrite(bp);
 269                 }
 270         }
 271         /*
 272          * Get the data block, allocating if necessary.
 273          */
 274         if (nb == 0) {
 275                 pref = ext2_blkpref(ip, lbn, indirs[i].in_off, &bap[0],
 276                                 bp->b_lblkno);
 277                 if ((error = ext2_alloc(ip,
 278                     lbn, pref, (int)fs->s_blocksize, cred, &newb)) != 0) {
 279                         brelse(bp);
 280                         return (error);
 281                 }
 282                 nb = newb;
 283                 nbp = getblk(vp, lbn, fs->s_blocksize, 0, 0);
 284                 nbp->b_blkno = fsbtodb(fs, nb);
 285                 if (flags & B_CLRBUF)
 286                         vfs_bio_clrbuf(nbp);
 287                 bap[indirs[i].in_off] = nb;
 288                 /*
 289                  * If required, write synchronously, otherwise use
 290                  * delayed write.
 291                  */
 292                 if (flags & B_SYNC) {
 293                         bwrite(bp);
 294                 } else {
 295                         bdwrite(bp);
 296                 }
 297                 *bpp = nbp;
 298                 return (0);
 299         }
 300         brelse(bp);
 301         if (flags & B_CLRBUF) {
 302                 error = bread(vp, lbn, (int)fs->s_blocksize, NOCRED, &nbp);
 303                 if (error) {
 304                         brelse(nbp);
 305                         return (error);
 306                 }
 307         } else {
 308                 nbp = getblk(vp, lbn, fs->s_blocksize, 0, 0);
 309                 nbp->b_blkno = fsbtodb(fs, nb);
 310         }
 311         *bpp = nbp;
 312         return (0);
 313 }