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  * 4. Neither the name of the University nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  *
  35  *      @(#)ffs_balloc.c        8.4 (Berkeley) 9/23/93
  36  * $FreeBSD$
  37  */
  38
  39 #include <sys/param.h>
  40 #include <sys/systm.h>
  41 #include <sys/bio.h>
  42 #include <sys/buf.h>
  43 #include <sys/lock.h>
  44 #include <sys/ucred.h>
  45 #include <sys/vnode.h>
  46
  47 #include <gnu/fs/ext2fs/inode.h>
  48 #include <gnu/fs/ext2fs/ext2_fs.h>
  49 #include <gnu/fs/ext2fs/ext2_fs_sb.h>
  50 #include <gnu/fs/ext2fs/fs.h>
  51 #include <gnu/fs/ext2fs/ext2_extern.h>
  52
  53 /*
  54  * Balloc defines the structure of file system storage
  55  * by allocating the physical blocks on a device given
  56  * the inode and the logical block number in a file.
  57  */
  58 int
  59 ext2_balloc(ip, bn, size, cred, bpp, flags)
  60         struct inode *ip;
  61         int32_t bn;
  62         int size;
  63         struct ucred *cred;
  64         struct buf **bpp;
  65         int flags;
  66 {
  67         struct ext2_sb_info *fs;
  68         int32_t nb;
  69         struct buf *bp, *nbp;
  70         struct vnode *vp = ITOV(ip);
  71         struct indir indirs[NIADDR + 2];
  72         int32_t newb, lbn, *bap, pref;
  73         int osize, nsize, num, i, error;
  74 /*
  75 ext2_debug("ext2_balloc called (%d, %d, %d)\n",
  76         ip->i_number, (int)bn, (int)size);
  77 */
  78         *bpp = NULL;
  79         if (bn < 0)
  80                 return (EFBIG);
  81         fs = ip->i_e2fs;
  82         lbn = bn;
  83
  84         /*
  85          * check if this is a sequential block allocation.
  86          * If so, increment next_alloc fields to allow ext2_blkpref
  87          * to make a good guess
  88          */
  89         if (lbn == ip->i_next_alloc_block + 1) {
  90                 ip->i_next_alloc_block++;
  91                 ip->i_next_alloc_goal++;
  92         }
  93
  94         /*
  95          * The first NDADDR blocks are direct blocks
  96          */
  97         if (bn < NDADDR) {
  98                 nb = ip->i_db[bn];
  99                 /* no new block is to be allocated, and no need to expand
 100                    the file */
 101                 if (nb != 0 && ip->i_size >= (bn + 1) * fs->s_blocksize) {
 102                         error = bread(vp, bn, fs->s_blocksize, NOCRED, &bp);
 103                         if (error) {
 104                                 brelse(bp);
 105                                 return (error);
 106                         }
 107                         bp->b_blkno = fsbtodb(fs, nb);
 108                         *bpp = bp;
 109                         return (0);
 110                 }
 111                 if (nb != 0) {
 112                         /*
 113                          * Consider need to reallocate a fragment.
 114                          */
 115                         osize = fragroundup(fs, blkoff(fs, ip->i_size));
 116                         nsize = fragroundup(fs, size);
 117                         if (nsize <= osize) {
 118                                 error = bread(vp, bn, osize, NOCRED, &bp);
 119                                 if (error) {
 120                                         brelse(bp);
 121                                         return (error);
 122                                 }
 123                                 bp->b_blkno = fsbtodb(fs, nb);
 124                         } else {
 125                         /* Godmar thinks: this shouldn't happen w/o fragments */
 126                                 printf("nsize %d(%d) > osize %d(%d) nb %d\n",
 127                                         (int)nsize, (int)size, (int)osize,
 128                                         (int)ip->i_size, (int)nb);
 129                                 panic(
 130                                     "ext2_balloc: Something is terribly wrong");
 131 /*
 132  * please note there haven't been any changes from here on -
 133  * FFS seems to work.
 134  */
 135                         }
 136                 } else {
 137                         if (ip->i_size < (bn + 1) * fs->s_blocksize)
 138                                 nsize = fragroundup(fs, size);
 139                         else
 140                                 nsize = fs->s_blocksize;
 141                         error = ext2_alloc(ip, bn,
 142                             ext2_blkpref(ip, bn, (int)bn, &ip->i_db[0], 0),
 143                             nsize, cred, &newb);
 144                         if (error)
 145                                 return (error);
 146                         bp = getblk(vp, bn, nsize, 0, 0, 0);
 147                         bp->b_blkno = fsbtodb(fs, newb);
 148                         if (flags & B_CLRBUF)
 149                                 vfs_bio_clrbuf(bp);
 150                 }
 151                 ip->i_db[bn] = dbtofsb(fs, bp->b_blkno);
 152                 ip->i_flag |= IN_CHANGE | IN_UPDATE;
 153                 *bpp = bp;
 154                 return (0);
 155         }
 156         /*
 157          * Determine the number of levels of indirection.
 158          */
 159         pref = 0;
 160         if ((error = ext2_getlbns(vp, bn, indirs, &num)) != 0)
 161                 return(error);
 162 #ifdef DIAGNOSTIC
 163         if (num < 1)
 164                 panic ("ext2_balloc: ext2_getlbns returned indirect block");
 165 #endif
 166         /*
 167          * Fetch the first indirect block allocating if necessary.
 168          */
 169         --num;
 170         nb = ip->i_ib[indirs[0].in_off];
 171         if (nb == 0) {
 172 #if 0
 173                 pref = ext2_blkpref(ip, lbn, 0, (int32_t *)0, 0);
 174 #else
 175                 /* see the comment by ext2_blkpref. What we do here is
 176                    to pretend that it'd be good for a block holding indirect
 177                    pointers to be allocated near its predecessor in terms
 178                    of indirection, or the last direct block.
 179                    We shamelessly exploit the fact that i_ib immediately
 180                    follows i_db.
 181                    Godmar thinks it make sense to allocate i_ib[0] immediately
 182                    after i_db[11], but it's not utterly clear whether this also
 183                    applies to i_ib[1] and i_ib[0]
 184                 */
 185
 186                 pref = ext2_blkpref(ip, lbn, indirs[0].in_off +
 187                                              EXT2_NDIR_BLOCKS, &ip->i_db[0], 0);
 188 #endif
 189                 if ((error = ext2_alloc(ip, lbn, pref, (int)fs->s_blocksize,
 190                     cred, &newb)) != 0)
 191                         return (error);
 192                 nb = newb;
 193                 bp = getblk(vp, indirs[1].in_lbn, fs->s_blocksize, 0, 0, 0);
 194                 bp->b_blkno = fsbtodb(fs, newb);
 195                 vfs_bio_clrbuf(bp);
 196                 /*
 197                  * Write synchronously so that indirect blocks
 198                  * never point at garbage.
 199                  */
 200                 if ((error = bwrite(bp)) != 0) {
 201                         ext2_blkfree(ip, nb, fs->s_blocksize);
 202                         return (error);
 203                 }
 204                 ip->i_ib[indirs[0].in_off] = newb;
 205                 ip->i_flag |= IN_CHANGE | IN_UPDATE;
 206         }
 207         /*
 208          * Fetch through the indirect blocks, allocating as necessary.
 209          */
 210         for (i = 1;;) {
 211                 error = bread(vp,
 212                     indirs[i].in_lbn, (int)fs->s_blocksize, NOCRED, &bp);
 213                 if (error) {
 214                         brelse(bp);
 215                         return (error);
 216                 }
 217                 bap = (int32_t *)bp->b_data;
 218                 nb = bap[indirs[i].in_off];
 219                 if (i == num)
 220                         break;
 221                 i += 1;
 222                 if (nb != 0) {
 223                         brelse(bp);
 224                         continue;
 225                 }
 226                 if (pref == 0)
 227 #if 1
 228                         /* see the comment above and by ext2_blkpref
 229                          * I think this implements Linux policy, but
 230                          * does it really make sense to allocate to
 231                          * block containing pointers together ?
 232                          * Also, will it ever succeed ?
 233                          */
 234                         pref = ext2_blkpref(ip, lbn, indirs[i].in_off, bap,
 235                                                 bp->b_lblkno);
 236 #else
 237                         pref = ext2_blkpref(ip, lbn, 0, (int32_t *)0, 0);
 238 #endif
 239                 if ((error =
 240                     ext2_alloc(ip, lbn, pref, (int)fs->s_blocksize, cred, &newb)) != 0) {
 241                         brelse(bp);
 242                         return (error);
 243                 }
 244                 nb = newb;
 245                 nbp = getblk(vp, indirs[i].in_lbn, fs->s_blocksize, 0, 0, 0);
 246                 nbp->b_blkno = fsbtodb(fs, nb);
 247                 vfs_bio_clrbuf(nbp);
 248                 /*
 249                  * Write synchronously so that indirect blocks
 250                  * never point at garbage.
 251                  */
 252                 if ((error = bwrite(nbp)) != 0) {
 253                         ext2_blkfree(ip, nb, fs->s_blocksize);
 254                         brelse(bp);
 255                         return (error);
 256                 }
 257                 bap[indirs[i - 1].in_off] = nb;
 258                 /*
 259                  * If required, write synchronously, otherwise use
 260                  * delayed write.
 261                  */
 262                 if (flags & B_SYNC) {
 263                         bwrite(bp);
 264                 } else {
 265                         bdwrite(bp);
 266                 }
 267         }
 268         /*
 269          * Get the data block, allocating if necessary.
 270          */
 271         if (nb == 0) {
 272                 pref = ext2_blkpref(ip, lbn, indirs[i].in_off, &bap[0],
 273                                 bp->b_lblkno);
 274                 if ((error = ext2_alloc(ip,
 275                     lbn, pref, (int)fs->s_blocksize, cred, &newb)) != 0) {
 276                         brelse(bp);
 277                         return (error);
 278                 }
 279                 nb = newb;
 280                 nbp = getblk(vp, lbn, fs->s_blocksize, 0, 0, 0);
 281                 nbp->b_blkno = fsbtodb(fs, nb);
 282                 if (flags & B_CLRBUF)
 283                         vfs_bio_clrbuf(nbp);
 284                 bap[indirs[i].in_off] = nb;
 285                 /*
 286                  * If required, write synchronously, otherwise use
 287                  * delayed write.
 288                  */
 289                 if (flags & B_SYNC) {
 290                         bwrite(bp);
 291                 } else {
 292                         bdwrite(bp);
 293                 }
 294                 *bpp = nbp;
 295                 return (0);
 296         }
 297         brelse(bp);
 298         if (flags & B_CLRBUF) {
 299                 error = bread(vp, lbn, (int)fs->s_blocksize, NOCRED, &nbp);
 300                 if (error) {
 301                         brelse(nbp);
 302                         return (error);
 303                 }
 304         } else {
 305                 nbp = getblk(vp, lbn, fs->s_blocksize, 0, 0, 0);
 306                 nbp->b_blkno = fsbtodb(fs, nb);
 307         }
 308         *bpp = nbp;
 309         return (0);
 310 }