sys/gnu/vfs/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 "quota.h"
  51 #include "inode.h"
  52 #include "ext2_fs.h"
  53 #include "ext2_fs_sb.h"
  54 #include "fs.h"
  55 #include "ext2_extern.h"
  56
  57 /*
  58  * Balloc defines the structure of file system storage
  59  * by allocating the physical blocks on a device given
  60  * the inode and the logical block number in a file.
  61  */
  62 int
  63 ext2_balloc(struct inode *ip, daddr_t bn, int size, struct ucred *cred,
  64             struct buf **bpp, int flags)
  65 {
  66         struct ext2_sb_info *fs;
  67         daddr_t nb;
  68         struct buf *bp, *nbp;
  69         struct vnode *vp = ITOV(ip);
  70         struct indir indirs[NIADDR + 2];
  71         daddr_t newb, lbn, *bap, pref;
  72         int osize, nsize, num, i, error;
  73 /*
  74 ext2_debug("ext2_balloc called (%d, %d, %d)\n",
  75         ip->i_number, (int)bn, (int)size);
  76 */
  77         *bpp = NULL;
  78         if (bn < 0)
  79                 return (EFBIG);
  80         fs = ip->i_e2fs;
  81         lbn = bn;
  82
  83         /*
  84          * check if this is a sequential block allocation.
  85          * If so, increment next_alloc fields to allow ext2_blkpref
  86          * to make a good guess
  87          */
  88         if (lbn == ip->i_next_alloc_block + 1) {
  89                 ip->i_next_alloc_block++;
  90                 ip->i_next_alloc_goal++;
  91         }
  92
  93         /*
  94          * The first NDADDR blocks are direct blocks
  95          */
  96         if (bn < NDADDR) {
  97                 nb = ip->i_db[bn];
  98                 /* no new block is to be allocated, and no need to expand
  99                    the file */
 100                 if (nb != 0 && ip->i_size >= (bn + 1) * fs->s_blocksize) {
 101                         error = bread(vp, lblktodoff(fs, bn),
 102                                       fs->s_blocksize, &bp);
 103                         if (error) {
 104                                 brelse(bp);
 105                                 return (error);
 106                         }
 107                         *bpp = bp;
 108                         return (0);
 109                 }
 110                 if (nb != 0) {
 111                         /*
 112                          * Consider need to reallocate a fragment.
 113                          */
 114                         osize = fragroundup(fs, blkoff(fs, ip->i_size));
 115                         nsize = fragroundup(fs, size);
 116                         if (nsize <= osize) {
 117                                 error = bread(vp, lblktodoff(fs, bn),
 118                                               osize, &bp);
 119                                 if (error) {
 120                                         brelse(bp);
 121                                         return (error);
 122                                 }
 123                         } else {
 124                         /* Godmar thinks: this shouldn't happen w/o fragments */
 125                                 kprintf("nsize %d(%d) > osize %d(%d) nb %d\n",
 126                                         (int)nsize, (int)size, (int)osize,
 127                                         (int)ip->i_size, (int)nb);
 128                                 panic(
 129                                     "ext2_balloc: Something is terribly wrong");
 130 /*
 131  * please note there haven't been any changes from here on -
 132  * FFS seems to work.
 133  */
 134                         }
 135                 } else {
 136                         if (ip->i_size < (bn + 1) * fs->s_blocksize)
 137                                 nsize = fragroundup(fs, size);
 138                         else
 139                                 nsize = fs->s_blocksize;
 140                         error = ext2_alloc(ip, bn,
 141                             ext2_blkpref(ip, bn, (int)bn, &ip->i_db[0], 0),
 142                             nsize, cred, &newb);
 143                         if (error)
 144                                 return (error);
 145                         bp = getblk(vp, lblktodoff(fs, bn), nsize, 0, 0);
 146                         bp->b_bio2.bio_offset = fsbtodoff(fs, newb);
 147                         if (flags & B_CLRBUF)
 148                                 vfs_bio_clrbuf(bp);
 149                 }
 150                 ip->i_db[bn] = dofftofsb(fs, bp->b_bio2.bio_offset);
 151                 ip->i_flag |= IN_CHANGE | IN_UPDATE;
 152                 *bpp = bp;
 153                 return (0);
 154         }
 155         /*
 156          * Determine the number of levels of indirection.
 157          */
 158         pref = 0;
 159         if ((error = ext2_getlbns(vp, bn, indirs, &num)) != 0)
 160                 return(error);
 161 #if DIAGNOSTIC
 162         if (num < 1)
 163                 panic ("ext2_balloc: ext2_bmaparray returned indirect block");
 164 #endif
 165         /*
 166          * Fetch the first indirect block allocating if necessary.
 167          */
 168         --num;
 169         nb = ip->i_ib[indirs[0].in_off];
 170         if (nb == 0) {
 171 #if 0
 172                 pref = ext2_blkpref(ip, lbn, 0, NULL, 0);
 173 #else
 174                 /* see the comment by ext2_blkpref. What we do here is
 175                    to pretend that it'd be good for a block holding indirect
 176                    pointers to be allocated near its predecessor in terms
 177                    of indirection, or the last direct block.
 178                    We shamelessly exploit the fact that i_ib immediately
 179                    follows i_db.
 180                    Godmar thinks it make sense to allocate i_ib[0] immediately
 181                    after i_db[11], but it's not utterly clear whether this also
 182                    applies to i_ib[1] and i_ib[0]
 183                 */
 184
 185                 pref = ext2_blkpref(ip, lbn, indirs[0].in_off +
 186                                              EXT2_NDIR_BLOCKS, &ip->i_db[0], 0);
 187 #endif
 188                 if ((error = ext2_alloc(ip, lbn, pref, (int)fs->s_blocksize,
 189                     cred, &newb)) != 0)
 190                         return (error);
 191                 nb = newb;
 192                 bp = getblk(vp, lblktodoff(fs, indirs[1].in_lbn),
 193                             fs->s_blocksize, 0, 0);
 194                 bp->b_bio2.bio_offset = fsbtodoff(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                               lblktodoff(fs, indirs[i].in_lbn),
 213                               (int)fs->s_blocksize, &bp);
 214                 if (error) {
 215                         brelse(bp);
 216                         return (error);
 217                 }
 218                 bap = (daddr_t *)bp->b_data;
 219                 nb = bap[indirs[i].in_off];
 220                 if (i == num)
 221                         break;
 222                 i += 1;
 223                 if (nb != 0) {
 224                         brelse(bp);
 225                         continue;
 226                 }
 227                 if (pref == 0)
 228 #if 1
 229                         /* see the comment above and by ext2_blkpref
 230                          * I think this implements Linux policy, but
 231                          * does it really make sense to allocate to
 232                          * block containing pointers together ?
 233                          * Also, will it ever succeed ?
 234                          */
 235                         pref = ext2_blkpref(ip, lbn, indirs[i].in_off, bap,
 236                                                 lblkno(fs, bp->b_loffset));
 237 #else
 238                         pref = ext2_blkpref(ip, lbn, 0, NULL, 0);
 239 #endif
 240                 if ((error =
 241                     ext2_alloc(ip, lbn, pref, (int)fs->s_blocksize, cred, &newb)) != 0) {
 242                         brelse(bp);
 243                         return (error);
 244                 }
 245                 nb = newb;
 246                 nbp = getblk(vp, lblktodoff(fs, indirs[i].in_lbn),
 247                              fs->s_blocksize, 0, 0);
 248                 nbp->b_bio2.bio_offset = fsbtodoff(fs, nb);
 249                 vfs_bio_clrbuf(nbp);
 250                 /*
 251                  * Write synchronously so that indirect blocks
 252                  * never point at garbage.
 253                  */
 254                 if ((error = bwrite(nbp)) != 0) {
 255                         ext2_blkfree(ip, nb, fs->s_blocksize);
 256                         brelse(bp);
 257                         return (error);
 258                 }
 259                 bap[indirs[i - 1].in_off] = nb;
 260                 /*
 261                  * If required, write synchronously, otherwise use
 262                  * delayed write.
 263                  */
 264                 if (flags & B_SYNC) {
 265                         bwrite(bp);
 266                 } else {
 267                         bdwrite(bp);
 268                 }
 269         }
 270         /*
 271          * Get the data block, allocating if necessary.
 272          */
 273         if (nb == 0) {
 274                 pref = ext2_blkpref(ip, lbn, indirs[i].in_off, &bap[0],
 275                                 lblkno(fs, bp->b_loffset));
 276                 if ((error = ext2_alloc(ip,
 277                     lbn, pref, (int)fs->s_blocksize, cred, &newb)) != 0) {
 278                         brelse(bp);
 279                         return (error);
 280                 }
 281                 nb = newb;
 282                 nbp = getblk(vp, lblktodoff(fs, lbn), fs->s_blocksize, 0, 0);
 283                 nbp->b_bio2.bio_offset = fsbtodoff(fs, nb);
 284                 if (flags & B_CLRBUF)
 285                         vfs_bio_clrbuf(nbp);
 286                 bap[indirs[i].in_off] = nb;
 287                 /*
 288                  * If required, write synchronously, otherwise use
 289                  * delayed write.
 290                  */
 291                 if (flags & B_SYNC) {
 292                         bwrite(bp);
 293                 } else {
 294                         bdwrite(bp);
 295                 }
 296                 *bpp = nbp;
 297                 return (0);
 298         }
 299         brelse(bp);
 300         if (flags & B_CLRBUF) {
 301                 error = bread(vp, lblktodoff(fs, lbn),
 302                               (int)fs->s_blocksize, &nbp);
 303                 if (error) {
 304                         brelse(nbp);
 305                         return (error);
 306                 }
 307         } else {
 308                 nbp = getblk(vp, lblktodoff(fs, lbn), fs->s_blocksize, 0, 0);
 309                 nbp->b_bio2.bio_offset = fsbtodoff(fs, nb);
 310         }
 311         *bpp = nbp;
 312         return (0);
 313 }