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  * $DragonFly: src/sys/vfs/gnu/ext2fs/ext2_balloc.c,v 1.2 2003/06/17 04:28:33 dillon Exp $
  42  */
  43
  44 #include <sys/param.h>
  45 #include <sys/systm.h>
  46 #include <sys/buf.h>
  47 #include <sys/lock.h>
  48 #include <sys/ucred.h>
  49 #include <sys/vnode.h>
  50
  51 #include <ufs/ufs/quota.h>
  52 #include <ufs/ufs/inode.h>
  53 #include <ufs/ufs/ufs_extern.h>
  54
  55 #include <gnu/ext2fs/ext2_fs.h>
  56 #include <gnu/ext2fs/ext2_fs_sb.h>
  57 #include <gnu/ext2fs/fs.h>
  58 #include <gnu/ext2fs/ext2_extern.h>
  59
  60 /*
  61  * Balloc defines the structure of file system storage
  62  * by allocating the physical blocks on a device given
  63  * the inode and the logical block number in a file.
  64  */
  65 int
  66 ext2_balloc(ip, bn, size, cred, bpp, flags)
  67         register struct inode *ip;
  68         register daddr_t bn;
  69         int size;
  70         struct ucred *cred;
  71         struct buf **bpp;
  72         int flags;
  73 {
  74         register struct ext2_sb_info *fs;
  75         register daddr_t nb;
  76         struct buf *bp, *nbp;
  77         struct vnode *vp = ITOV(ip);
  78         struct indir indirs[NIADDR + 2];
  79         daddr_t newb, lbn, *bap, pref;
  80         int osize, nsize, num, i, error;
  81 /*
  82 ext2_debug("ext2_balloc called (%d, %d, %d)\n",
  83         ip->i_number, (int)bn, (int)size);
  84 */
  85         *bpp = NULL;
  86         if (bn < 0)
  87                 return (EFBIG);
  88         fs = ip->i_e2fs;
  89         lbn = bn;
  90
  91         /*
  92          * check if this is a sequential block allocation.
  93          * If so, increment next_alloc fields to allow ext2_blkpref
  94          * to make a good guess
  95          */
  96         if (lbn == ip->i_next_alloc_block + 1) {
  97                 ip->i_next_alloc_block++;
  98                 ip->i_next_alloc_goal++;
  99         }
 100
 101         /*
 102          * The first NDADDR blocks are direct blocks
 103          */
 104         if (bn < NDADDR) {
 105                 nb = ip->i_db[bn];
 106                 /* no new block is to be allocated, and no need to expand
 107                    the file */
 108                 if (nb != 0 && ip->i_size >= (bn + 1) * fs->s_blocksize) {
 109                         error = bread(vp, bn, fs->s_blocksize, NOCRED, &bp);
 110                         if (error) {
 111                                 brelse(bp);
 112                                 return (error);
 113                         }
 114                         *bpp = bp;
 115                         return (0);
 116                 }
 117                 if (nb != 0) {
 118                         /*
 119                          * Consider need to reallocate a fragment.
 120                          */
 121                         osize = fragroundup(fs, blkoff(fs, ip->i_size));
 122                         nsize = fragroundup(fs, size);
 123                         if (nsize <= osize) {
 124                                 error = bread(vp, bn, osize, NOCRED, &bp);
 125                                 if (error) {
 126                                         brelse(bp);
 127                                         return (error);
 128                                 }
 129                         } else {
 130                         /* Godmar thinks: this shouldn't happen w/o fragments */
 131                                 printf("nsize %d(%d) > osize %d(%d) nb %d\n",
 132                                         (int)nsize, (int)size, (int)osize,
 133                                         (int)ip->i_size, (int)nb);
 134                                 panic(
 135                                     "ext2_balloc: Something is terribly wrong");
 136 /*
 137  * please note there haven't been any changes from here on -
 138  * FFS seems to work.
 139  */
 140                         }
 141                 } else {
 142                         if (ip->i_size < (bn + 1) * fs->s_blocksize)
 143                                 nsize = fragroundup(fs, size);
 144                         else
 145                                 nsize = fs->s_blocksize;
 146                         error = ext2_alloc(ip, bn,
 147                             ext2_blkpref(ip, bn, (int)bn, &ip->i_db[0], 0),
 148                             nsize, cred, &newb);
 149                         if (error)
 150                                 return (error);
 151                         bp = getblk(vp, bn, nsize, 0, 0);
 152                         bp->b_blkno = fsbtodb(fs, newb);
 153                         if (flags & B_CLRBUF)
 154                                 vfs_bio_clrbuf(bp);
 155                 }
 156                 ip->i_db[bn] = dbtofsb(fs, bp->b_blkno);
 157                 ip->i_flag |= IN_CHANGE | IN_UPDATE;
 158                 *bpp = bp;
 159                 return (0);
 160         }
 161         /*
 162          * Determine the number of levels of indirection.
 163          */
 164         pref = 0;
 165         if ((error = ufs_getlbns(vp, bn, indirs, &num)) != 0)
 166                 return(error);
 167 #if DIAGNOSTIC
 168         if (num < 1)
 169                 panic ("ext2_balloc: ufs_bmaparray returned indirect block");
 170 #endif
 171         /*
 172          * Fetch the first indirect block allocating if necessary.
 173          */
 174         --num;
 175         nb = ip->i_ib[indirs[0].in_off];
 176         if (nb == 0) {
 177 #if 0
 178                 pref = ext2_blkpref(ip, lbn, 0, (daddr_t *)0, 0);
 179 #else
 180                 /* see the comment by ext2_blkpref. What we do here is
 181                    to pretend that it'd be good for a block holding indirect
 182                    pointers to be allocated near its predecessor in terms
 183                    of indirection, or the last direct block.
 184                    We shamelessly exploit the fact that i_ib immediately
 185                    follows i_db.
 186                    Godmar thinks it make sense to allocate i_ib[0] immediately
 187                    after i_db[11], but it's not utterly clear whether this also
 188                    applies to i_ib[1] and i_ib[0]
 189                 */
 190
 191                 pref = ext2_blkpref(ip, lbn, indirs[0].in_off +
 192                                              EXT2_NDIR_BLOCKS, &ip->i_db[0], 0);
 193 #endif
 194                 if ((error = ext2_alloc(ip, lbn, pref, (int)fs->s_blocksize,
 195                     cred, &newb)) != 0)
 196                         return (error);
 197                 nb = newb;
 198                 bp = getblk(vp, indirs[1].in_lbn, fs->s_blocksize, 0, 0);
 199                 bp->b_blkno = fsbtodb(fs, newb);
 200                 vfs_bio_clrbuf(bp);
 201                 /*
 202                  * Write synchronously so that indirect blocks
 203                  * never point at garbage.
 204                  */
 205                 if ((error = bwrite(bp)) != 0) {
 206                         ext2_blkfree(ip, nb, fs->s_blocksize);
 207                         return (error);
 208                 }
 209                 ip->i_ib[indirs[0].in_off] = newb;
 210                 ip->i_flag |= IN_CHANGE | IN_UPDATE;
 211         }
 212         /*
 213          * Fetch through the indirect blocks, allocating as necessary.
 214          */
 215         for (i = 1;;) {
 216                 error = bread(vp,
 217                     indirs[i].in_lbn, (int)fs->s_blocksize, NOCRED, &bp);
 218                 if (error) {
 219                         brelse(bp);
 220                         return (error);
 221                 }
 222                 bap = (daddr_t *)bp->b_data;
 223                 nb = bap[indirs[i].in_off];
 224                 if (i == num)
 225                         break;
 226                 i += 1;
 227                 if (nb != 0) {
 228                         brelse(bp);
 229                         continue;
 230                 }
 231                 if (pref == 0)
 232 #if 1
 233                         /* see the comment above and by ext2_blkpref
 234                          * I think this implements Linux policy, but
 235                          * does it really make sense to allocate to
 236                          * block containing pointers together ?
 237                          * Also, will it ever succeed ?
 238                          */
 239                         pref = ext2_blkpref(ip, lbn, indirs[i].in_off, bap,
 240                                                 bp->b_lblkno);
 241 #else
 242                         pref = ext2_blkpref(ip, lbn, 0, (daddr_t *)0, 0);
 243 #endif
 244                 if ((error =
 245                     ext2_alloc(ip, lbn, pref, (int)fs->s_blocksize, cred, &newb)) != 0) {
 246                         brelse(bp);
 247                         return (error);
 248                 }
 249                 nb = newb;
 250                 nbp = getblk(vp, indirs[i].in_lbn, fs->s_blocksize, 0, 0);
 251                 nbp->b_blkno = fsbtodb(fs, nb);
 252                 vfs_bio_clrbuf(nbp);
 253                 /*
 254                  * Write synchronously so that indirect blocks
 255                  * never point at garbage.
 256                  */
 257                 if ((error = bwrite(nbp)) != 0) {
 258                         ext2_blkfree(ip, nb, fs->s_blocksize);
 259                         brelse(bp);
 260                         return (error);
 261                 }
 262                 bap[indirs[i - 1].in_off] = nb;
 263                 /*
 264                  * If required, write synchronously, otherwise use
 265                  * delayed write.
 266                  */
 267                 if (flags & B_SYNC) {
 268                         bwrite(bp);
 269                 } else {
 270                         bdwrite(bp);
 271                 }
 272         }
 273         /*
 274          * Get the data block, allocating if necessary.
 275          */
 276         if (nb == 0) {
 277                 pref = ext2_blkpref(ip, lbn, indirs[i].in_off, &bap[0],
 278                                 bp->b_lblkno);
 279                 if ((error = ext2_alloc(ip,
 280                     lbn, pref, (int)fs->s_blocksize, cred, &newb)) != 0) {
 281                         brelse(bp);
 282                         return (error);
 283                 }
 284                 nb = newb;
 285                 nbp = getblk(vp, lbn, fs->s_blocksize, 0, 0);
 286                 nbp->b_blkno = fsbtodb(fs, nb);
 287                 if (flags & B_CLRBUF)
 288                         vfs_bio_clrbuf(nbp);
 289                 bap[indirs[i].in_off] = nb;
 290                 /*
 291                  * If required, write synchronously, otherwise use
 292                  * delayed write.
 293                  */
 294                 if (flags & B_SYNC) {
 295                         bwrite(bp);
 296                 } else {
 297                         bdwrite(bp);
 298                 }
 299                 *bpp = nbp;
 300                 return (0);
 301         }
 302         brelse(bp);
 303         if (flags & B_CLRBUF) {
 304                 error = bread(vp, lbn, (int)fs->s_blocksize, NOCRED, &nbp);
 305                 if (error) {
 306                         brelse(nbp);
 307                         return (error);
 308                 }
 309         } else {
 310                 nbp = getblk(vp, lbn, fs->s_blocksize, 0, 0);
 311                 nbp->b_blkno = fsbtodb(fs, nb);
 312         }
 313         *bpp = nbp;
 314         return (0);
 315 }