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 <sys/buf2.h>
  51
  52 #include "quota.h"
  53 #include "inode.h"
  54 #include "ext2_fs.h"
  55 #include "ext2_fs_sb.h"
  56 #include "fs.h"
  57 #include "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(struct inode *ip, daddr_t bn, int size, struct ucred *cred,
  66             struct buf **bpp, int flags)
  67 {
  68         struct ext2_sb_info *fs;
  69         daddr_t nb;
  70         struct buf *bp, *nbp;
  71         struct vnode *vp = ITOV(ip);
  72         struct indir indirs[NIADDR + 2];
  73         daddr_t newb, lbn, *bap, pref;
  74         int osize, nsize, num, i, error;
  75 /*
  76 ext2_debug("ext2_balloc called (%d, %d, %d)\n",
  77         ip->i_number, (int)bn, (int)size);
  78 */
  79         *bpp = NULL;
  80         if (bn < 0)
  81                 return (EFBIG);
  82         fs = ip->i_e2fs;
  83         lbn = bn;
  84
  85         /*
  86          * check if this is a sequential block allocation.
  87          * If so, increment next_alloc fields to allow ext2_blkpref
  88          * to make a good guess
  89          */
  90         if (lbn == ip->i_next_alloc_block + 1) {
  91                 ip->i_next_alloc_block++;
  92                 ip->i_next_alloc_goal++;
  93         }
  94
  95         /*
  96          * The first NDADDR blocks are direct blocks
  97          */
  98         if (bn < NDADDR) {
  99                 nb = ip->i_db[bn];
 100                 /* no new block is to be allocated, and no need to expand
 101                    the file */
 102                 if (nb != 0 && ip->i_size >= (bn + 1) * fs->s_blocksize) {
 103                         error = bread(vp, lblktodoff(fs, bn),
 104                                       fs->s_blocksize, &bp);
 105                         if (error) {
 106                                 brelse(bp);
 107                                 return (error);
 108                         }
 109                         *bpp = bp;
 110                         return (0);
 111                 }
 112                 if (nb != 0) {
 113                         /*
 114                          * Consider need to reallocate a fragment.
 115                          */
 116                         osize = fragroundup(fs, blkoff(fs, ip->i_size));
 117                         nsize = fragroundup(fs, size);
 118                         if (nsize <= osize) {
 119                                 error = bread(vp, lblktodoff(fs, bn),
 120                                               osize, &bp);
 121                                 if (error) {
 122                                         brelse(bp);
 123                                         return (error);
 124                                 }
 125                         } else {
 126                         /* Godmar thinks: this shouldn't happen w/o fragments */
 127                                 kprintf("nsize %d(%d) > osize %d(%d) nb %d\n",
 128                                         (int)nsize, (int)size, (int)osize,
 129                                         (int)ip->i_size, (int)nb);
 130                                 panic(
 131                                     "ext2_balloc: Something is terribly wrong");
 132 /*
 133  * please note there haven't been any changes from here on -
 134  * FFS seems to work.
 135  */
 136                         }
 137                 } else {
 138                         if (ip->i_size < (bn + 1) * fs->s_blocksize)
 139                                 nsize = fragroundup(fs, size);
 140                         else
 141                                 nsize = fs->s_blocksize;
 142                         error = ext2_alloc(ip, bn,
 143                             ext2_blkpref(ip, bn, (int)bn, &ip->i_db[0], 0),
 144                             nsize, cred, &newb);
 145                         if (error)
 146                                 return (error);
 147                         bp = getblk(vp, lblktodoff(fs, bn), nsize, 0, 0);
 148                         bp->b_bio2.bio_offset = fsbtodoff(fs, newb);
 149                         if (flags & B_CLRBUF)
 150                                 vfs_bio_clrbuf(bp);
 151                 }
 152                 ip->i_db[bn] = dofftofsb(fs, bp->b_bio2.bio_offset);
 153                 ip->i_flag |= IN_CHANGE | IN_UPDATE;
 154                 *bpp = bp;
 155                 return (0);
 156         }
 157         /*
 158          * Determine the number of levels of indirection.
 159          */
 160         pref = 0;
 161         if ((error = ext2_getlbns(vp, bn, indirs, &num)) != 0)
 162                 return(error);
 163 #if DIAGNOSTIC
 164         if (num < 1)
 165                 panic ("ext2_balloc: ext2_bmaparray returned indirect block");
 166 #endif
 167         /*
 168          * Fetch the first indirect block allocating if necessary.
 169          */
 170         --num;
 171         nb = ip->i_ib[indirs[0].in_off];
 172         if (nb == 0) {
 173 #if 0
 174                 pref = ext2_blkpref(ip, lbn, 0, NULL, 0);
 175 #else
 176                 /* see the comment by ext2_blkpref. What we do here is
 177                    to pretend that it'd be good for a block holding indirect
 178                    pointers to be allocated near its predecessor in terms
 179                    of indirection, or the last direct block.
 180                    We shamelessly exploit the fact that i_ib immediately
 181                    follows i_db.
 182                    Godmar thinks it make sense to allocate i_ib[0] immediately
 183                    after i_db[11], but it's not utterly clear whether this also
 184                    applies to i_ib[1] and i_ib[0]
 185                 */
 186
 187                 pref = ext2_blkpref(ip, lbn, indirs[0].in_off +
 188                                              EXT2_NDIR_BLOCKS, &ip->i_db[0], 0);
 189 #endif
 190                 if ((error = ext2_alloc(ip, lbn, pref, (int)fs->s_blocksize,
 191                     cred, &newb)) != 0)
 192                         return (error);
 193                 nb = newb;
 194                 bp = getblk(vp, lblktodoff(fs, indirs[1].in_lbn),
 195                             fs->s_blocksize, 0, 0);
 196                 bp->b_bio2.bio_offset = fsbtodoff(fs, newb);
 197                 vfs_bio_clrbuf(bp);
 198                 /*
 199                  * Write synchronously so that indirect blocks
 200                  * never point at garbage.
 201                  */
 202                 if ((error = bwrite(bp)) != 0) {
 203                         ext2_blkfree(ip, nb, fs->s_blocksize);
 204                         return (error);
 205                 }
 206                 ip->i_ib[indirs[0].in_off] = newb;
 207                 ip->i_flag |= IN_CHANGE | IN_UPDATE;
 208         }
 209         /*
 210          * Fetch through the indirect blocks, allocating as necessary.
 211          */
 212         for (i = 1;;) {
 213                 error = bread(vp,
 214                               lblktodoff(fs, indirs[i].in_lbn),
 215                               (int)fs->s_blocksize, &bp);
 216                 if (error) {
 217                         brelse(bp);
 218                         return (error);
 219                 }
 220                 bap = (daddr_t *)bp->b_data;
 221                 nb = bap[indirs[i].in_off];
 222                 if (i == num)
 223                         break;
 224                 i += 1;
 225                 if (nb != 0) {
 226                         brelse(bp);
 227                         continue;
 228                 }
 229                 if (pref == 0)
 230 #if 1
 231                         /* see the comment above and by ext2_blkpref
 232                          * I think this implements Linux policy, but
 233                          * does it really make sense to allocate to
 234                          * block containing pointers together ?
 235                          * Also, will it ever succeed ?
 236                          */
 237                         pref = ext2_blkpref(ip, lbn, indirs[i].in_off, bap,
 238                                                 lblkno(fs, bp->b_loffset));
 239 #else
 240                         pref = ext2_blkpref(ip, lbn, 0, NULL, 0);
 241 #endif
 242                 if ((error =
 243                     ext2_alloc(ip, lbn, pref, (int)fs->s_blocksize, cred, &newb)) != 0) {
 244                         brelse(bp);
 245                         return (error);
 246                 }
 247                 nb = newb;
 248                 nbp = getblk(vp, lblktodoff(fs, indirs[i].in_lbn),
 249                              fs->s_blocksize, 0, 0);
 250                 nbp->b_bio2.bio_offset = fsbtodoff(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                                 lblkno(fs, bp->b_loffset));
 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, lblktodoff(fs, lbn), fs->s_blocksize, 0, 0);
 285                 nbp->b_bio2.bio_offset = fsbtodoff(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, lblktodoff(fs, lbn),
 304                               (int)fs->s_blocksize, &nbp);
 305                 if (error) {
 306                         brelse(nbp);
 307                         return (error);
 308                 }
 309         } else {
 310                 nbp = getblk(vp, lblktodoff(fs, lbn), fs->s_blocksize, 0, 0);
 311                 nbp->b_bio2.bio_offset = fsbtodoff(fs, nb);
 312         }
 313         *bpp = nbp;
 314         return (0);
 315 }