sys/vfs/gnu/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  * $FreeBSD: src/sys/gnu/ext2fs/ext2_balloc.c,v 1.9.2.1 2000/08/03 00:52:57 peter Exp $
  41  */
  42
  43 #include <sys/param.h>
  44 #include <sys/systm.h>
  45 #include <sys/buf.h>
  46 #include <sys/lock.h>
  47 #include <sys/ucred.h>
  48 #include <sys/vnode.h>
  49
  50 #include <ufs/ufs/quota.h>
  51 #include <ufs/ufs/inode.h>
  52 #include <ufs/ufs/ufs_extern.h>
  53
  54 #include <gnu/ext2fs/ext2_fs.h>
  55 #include <gnu/ext2fs/ext2_fs_sb.h>
  56 #include <gnu/ext2fs/fs.h>
  57 #include <gnu/ext2fs/ext2_extern.h>
  58
  59 /*
  60  * Balloc defines the structure of file system storage
  61  * by allocating the physical blocks on a device given
  62  * the inode and the logical block number in a file.
  63  */
  64 int
  65 ext2_balloc(ip, bn, size, cred, bpp, flags)
  66         register struct inode *ip;
  67         register daddr_t bn;
  68         int size;
  69         struct ucred *cred;
  70         struct buf **bpp;
  71         int flags;
  72 {
  73         register struct ext2_sb_info *fs;
  74         register daddr_t nb;
  75         struct buf *bp, *nbp;
  76         struct vnode *vp = ITOV(ip);
  77         struct indir indirs[NIADDR + 2];
  78         daddr_t newb, lbn, *bap, pref;
  79         int osize, nsize, num, i, error;
  80 /*
  81 ext2_debug("ext2_balloc called (%d, %d, %d)\n",
  82         ip->i_number, (int)bn, (int)size);
  83 */
  84         *bpp = NULL;
  85         if (bn < 0)
  86                 return (EFBIG);
  87         fs = ip->i_e2fs;
  88         lbn = bn;
  89
  90         /*
  91          * check if this is a sequential block allocation.
  92          * If so, increment next_alloc fields to allow ext2_blkpref
  93          * to make a good guess
  94          */
  95         if (lbn == ip->i_next_alloc_block + 1) {
  96                 ip->i_next_alloc_block++;
  97                 ip->i_next_alloc_goal++;
  98         }
  99
 100         /*
 101          * The first NDADDR blocks are direct blocks
 102          */
 103         if (bn < NDADDR) {
 104                 nb = ip->i_db[bn];
 105                 /* no new block is to be allocated, and no need to expand
 106                    the file */
 107                 if (nb != 0 && ip->i_size >= (bn + 1) * fs->s_blocksize) {
 108                         error = bread(vp, bn, fs->s_blocksize, NOCRED, &bp);
 109                         if (error) {
 110                                 brelse(bp);
 111                                 return (error);
 112                         }
 113                         *bpp = bp;
 114                         return (0);
 115                 }
 116                 if (nb != 0) {
 117                         /*
 118                          * Consider need to reallocate a fragment.
 119                          */
 120                         osize = fragroundup(fs, blkoff(fs, ip->i_size));
 121                         nsize = fragroundup(fs, size);
 122                         if (nsize <= osize) {
 123                                 error = bread(vp, bn, osize, NOCRED, &bp);
 124                                 if (error) {
 125                                         brelse(bp);
 126                                         return (error);
 127                                 }
 128                         } else {
 129                         /* Godmar thinks: this shouldn't happen w/o fragments */
 130                                 printf("nsize %d(%d) > osize %d(%d) nb %d\n",
 131                                         (int)nsize, (int)size, (int)osize,
 132                                         (int)ip->i_size, (int)nb);
 133                                 panic(
 134                                     "ext2_balloc: Something is terribly wrong");
 135 /*
 136  * please note there haven't been any changes from here on -
 137  * FFS seems to work.
 138  */
 139                         }
 140                 } else {
 141                         if (ip->i_size < (bn + 1) * fs->s_blocksize)
 142                                 nsize = fragroundup(fs, size);
 143                         else
 144                                 nsize = fs->s_blocksize;
 145                         error = ext2_alloc(ip, bn,
 146                             ext2_blkpref(ip, bn, (int)bn, &ip->i_db[0], 0),
 147                             nsize, cred, &newb);
 148                         if (error)
 149                                 return (error);
 150                         bp = getblk(vp, bn, nsize, 0, 0);
 151                         bp->b_blkno = fsbtodb(fs, newb);
 152                         if (flags & B_CLRBUF)
 153                                 vfs_bio_clrbuf(bp);
 154                 }
 155                 ip->i_db[bn] = dbtofsb(fs, bp->b_blkno);
 156                 ip->i_flag |= IN_CHANGE | IN_UPDATE;
 157                 *bpp = bp;
 158                 return (0);
 159         }
 160         /*
 161          * Determine the number of levels of indirection.
 162          */
 163         pref = 0;
 164         if ((error = ufs_getlbns(vp, bn, indirs, &num)) != 0)
 165                 return(error);
 166 #if DIAGNOSTIC
 167         if (num < 1)
 168                 panic ("ext2_balloc: ufs_bmaparray returned indirect block");
 169 #endif
 170         /*
 171          * Fetch the first indirect block allocating if necessary.
 172          */
 173         --num;
 174         nb = ip->i_ib[indirs[0].in_off];
 175         if (nb == 0) {
 176 #if 0
 177                 pref = ext2_blkpref(ip, lbn, 0, (daddr_t *)0, 0);
 178 #else
 179                 /* see the comment by ext2_blkpref. What we do here is
 180                    to pretend that it'd be good for a block holding indirect
 181                    pointers to be allocated near its predecessor in terms
 182                    of indirection, or the last direct block.
 183                    We shamelessly exploit the fact that i_ib immediately
 184                    follows i_db.
 185                    Godmar thinks it make sense to allocate i_ib[0] immediately
 186                    after i_db[11], but it's not utterly clear whether this also
 187                    applies to i_ib[1] and i_ib[0]
 188                 */
 189
 190                 pref = ext2_blkpref(ip, lbn, indirs[0].in_off +
 191                                              EXT2_NDIR_BLOCKS, &ip->i_db[0], 0);
 192 #endif
 193                 if ((error = ext2_alloc(ip, lbn, pref, (int)fs->s_blocksize,
 194                     cred, &newb)) != 0)
 195                         return (error);
 196                 nb = newb;
 197                 bp = getblk(vp, indirs[1].in_lbn, fs->s_blocksize, 0, 0);
 198                 bp->b_blkno = fsbtodb(fs, newb);
 199                 vfs_bio_clrbuf(bp);
 200                 /*
 201                  * Write synchronously so that indirect blocks
 202                  * never point at garbage.
 203                  */
 204                 if ((error = bwrite(bp)) != 0) {
 205                         ext2_blkfree(ip, nb, fs->s_blocksize);
 206                         return (error);
 207                 }
 208                 ip->i_ib[indirs[0].in_off] = newb;
 209                 ip->i_flag |= IN_CHANGE | IN_UPDATE;
 210         }
 211         /*
 212          * Fetch through the indirect blocks, allocating as necessary.
 213          */
 214         for (i = 1;;) {
 215                 error = bread(vp,
 216                     indirs[i].in_lbn, (int)fs->s_blocksize, NOCRED, &bp);
 217                 if (error) {
 218                         brelse(bp);
 219                         return (error);
 220                 }
 221                 bap = (daddr_t *)bp->b_data;
 222                 nb = bap[indirs[i].in_off];
 223                 if (i == num)
 224                         break;
 225                 i += 1;
 226                 if (nb != 0) {
 227                         brelse(bp);
 228                         continue;
 229                 }
 230                 if (pref == 0)
 231 #if 1
 232                         /* see the comment above and by ext2_blkpref
 233                          * I think this implements Linux policy, but
 234                          * does it really make sense to allocate to
 235                          * block containing pointers together ?
 236                          * Also, will it ever succeed ?
 237                          */
 238                         pref = ext2_blkpref(ip, lbn, indirs[i].in_off, bap,
 239                                                 bp->b_lblkno);
 240 #else
 241                         pref = ext2_blkpref(ip, lbn, 0, (daddr_t *)0, 0);
 242 #endif
 243                 if ((error =
 244                     ext2_alloc(ip, lbn, pref, (int)fs->s_blocksize, cred, &newb)) != 0) {
 245                         brelse(bp);
 246                         return (error);
 247                 }
 248                 nb = newb;
 249                 nbp = getblk(vp, indirs[i].in_lbn, fs->s_blocksize, 0, 0);
 250                 nbp->b_blkno = fsbtodb(fs, nb);
 251                 vfs_bio_clrbuf(nbp);
 252                 /*
 253                  * Write synchronously so that indirect blocks
 254                  * never point at garbage.
 255                  */
 256                 if ((error = bwrite(nbp)) != 0) {
 257                         ext2_blkfree(ip, nb, fs->s_blocksize);
 258                         brelse(bp);
 259                         return (error);
 260                 }
 261                 bap[indirs[i - 1].in_off] = nb;
 262                 /*
 263                  * If required, write synchronously, otherwise use
 264                  * delayed write.
 265                  */
 266                 if (flags & B_SYNC) {
 267                         bwrite(bp);
 268                 } else {
 269                         bdwrite(bp);
 270                 }
 271         }
 272         /*
 273          * Get the data block, allocating if necessary.
 274          */
 275         if (nb == 0) {
 276                 pref = ext2_blkpref(ip, lbn, indirs[i].in_off, &bap[0],
 277                                 bp->b_lblkno);
 278                 if ((error = ext2_alloc(ip,
 279                     lbn, pref, (int)fs->s_blocksize, cred, &newb)) != 0) {
 280                         brelse(bp);
 281                         return (error);
 282                 }
 283                 nb = newb;
 284                 nbp = getblk(vp, lbn, fs->s_blocksize, 0, 0);
 285                 nbp->b_blkno = fsbtodb(fs, nb);
 286                 if (flags & B_CLRBUF)
 287                         vfs_bio_clrbuf(nbp);
 288                 bap[indirs[i].in_off] = nb;
 289                 /*
 290                  * If required, write synchronously, otherwise use
 291                  * delayed write.
 292                  */
 293                 if (flags & B_SYNC) {
 294                         bwrite(bp);
 295                 } else {
 296                         bdwrite(bp);
 297                 }
 298                 *bpp = nbp;
 299                 return (0);
 300         }
 301         brelse(bp);
 302         if (flags & B_CLRBUF) {
 303                 error = bread(vp, lbn, (int)fs->s_blocksize, NOCRED, &nbp);
 304                 if (error) {
 305                         brelse(nbp);
 306                         return (error);
 307                 }
 308         } else {
 309                 nbp = getblk(vp, lbn, fs->s_blocksize, 0, 0);
 310                 nbp->b_blkno = fsbtodb(fs, nb);
 311         }
 312         *bpp = nbp;
 313         return (0);
 314 }