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 1.9 2006/04/04 17:34:32 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 "quota.h"
  52 #include "inode.h"
  53 #include "ext2_fs.h"
  54 #include "ext2_fs_sb.h"
  55 #include "fs.h"
  56 #include "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(struct inode *ip, daddr_t bn, int size, struct ucred *cred,
  65             struct buf **bpp, int flags)
  66 {
  67         struct ext2_sb_info *fs;
  68         daddr_t nb;
  69         struct buf *bp, *nbp;
  70         struct vnode *vp = ITOV(ip);
  71         struct indir indirs[NIADDR + 2];
  72         daddr_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, lblktodoff(fs, bn),
 103                                       fs->s_blocksize, &bp);
 104                         if (error) {
 105                                 brelse(bp);
 106                                 return (error);
 107                         }
 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, lblktodoff(fs, bn),
 119                                               osize, &bp);
 120                                 if (error) {
 121                                         brelse(bp);
 122                                         return (error);
 123                                 }
 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, lblktodoff(fs, bn), nsize, 0, 0);
 147                         bp->b_bio2.bio_offset = fsbtodoff(fs, newb);
 148                         if (flags & B_CLRBUF)
 149                                 vfs_bio_clrbuf(bp);
 150                 }
 151                 ip->i_db[bn] = dofftofsb(fs, bp->b_bio2.bio_offset);
 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 #if DIAGNOSTIC
 163         if (num < 1)
 164                 panic ("ext2_balloc: ext2_bmaparray 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, (daddr_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, lblktodoff(fs, indirs[1].in_lbn),
 194                             fs->s_blocksize, 0, 0);
 195                 bp->b_bio2.bio_offset = fsbtodoff(fs, newb);
 196                 vfs_bio_clrbuf(bp);
 197                 /*
 198                  * Write synchronously so that indirect blocks
 199                  * never point at garbage.
 200                  */
 201                 if ((error = bwrite(bp)) != 0) {
 202                         ext2_blkfree(ip, nb, fs->s_blocksize);
 203                         return (error);
 204                 }
 205                 ip->i_ib[indirs[0].in_off] = newb;
 206                 ip->i_flag |= IN_CHANGE | IN_UPDATE;
 207         }
 208         /*
 209          * Fetch through the indirect blocks, allocating as necessary.
 210          */
 211         for (i = 1;;) {
 212                 error = bread(vp,
 213                               lblktodoff(fs, indirs[i].in_lbn),
 214                               (int)fs->s_blocksize, &bp);
 215                 if (error) {
 216                         brelse(bp);
 217                         return (error);
 218                 }
 219                 bap = (daddr_t *)bp->b_data;
 220                 nb = bap[indirs[i].in_off];
 221                 if (i == num)
 222                         break;
 223                 i += 1;
 224                 if (nb != 0) {
 225                         brelse(bp);
 226                         continue;
 227                 }
 228                 if (pref == 0)
 229 #if 1
 230                         /* see the comment above and by ext2_blkpref
 231                          * I think this implements Linux policy, but
 232                          * does it really make sense to allocate to
 233                          * block containing pointers together ?
 234                          * Also, will it ever succeed ?
 235                          */
 236                         pref = ext2_blkpref(ip, lbn, indirs[i].in_off, bap,
 237                                                 lblkno(fs, bp->b_loffset));
 238 #else
 239                         pref = ext2_blkpref(ip, lbn, 0, (daddr_t *)0, 0);
 240 #endif
 241                 if ((error =
 242                     ext2_alloc(ip, lbn, pref, (int)fs->s_blocksize, cred, &newb)) != 0) {
 243                         brelse(bp);
 244                         return (error);
 245                 }
 246                 nb = newb;
 247                 nbp = getblk(vp, lblktodoff(fs, indirs[i].in_lbn),
 248                              fs->s_blocksize, 0, 0);
 249                 nbp->b_bio2.bio_offset = fsbtodoff(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                                 lblkno(fs, bp->b_loffset));
 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, lblktodoff(fs, lbn), fs->s_blocksize, 0, 0);
 284                 nbp->b_bio2.bio_offset = fsbtodoff(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, lblktodoff(fs, lbn),
 303                               (int)fs->s_blocksize, &nbp);
 304                 if (error) {
 305                         brelse(nbp);
 306                         return (error);
 307                 }
 308         } else {
 309                 nbp = getblk(vp, lblktodoff(fs, lbn), fs->s_blocksize, 0, 0);
 310                 nbp->b_bio2.bio_offset = fsbtodoff(fs, nb);
 311         }
 312         *bpp = nbp;
 313         return (0);
 314 }