sys/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/mount.h>
  45 #include <sys/vnode.h>
  46
  47 #include <fs/ext2fs/inode.h>
  48 #include <fs/ext2fs/ext2fs.h>
  49 #include <fs/ext2fs/fs.h>
  50 #include <fs/ext2fs/ext2_extern.h>
  51 #include <fs/ext2fs/ext2_mount.h>
  52 /*
  53  * Balloc defines the structure of file system storage
  54  * by allocating the physical blocks on a device given
  55  * the inode and the logical block number in a file.
  56  */
  57 int
  58 ext2_balloc(ip, lbn, size, cred, bpp, flags)
  59         struct inode *ip;
  60         int32_t lbn;
  61         int size;
  62         struct ucred *cred;
  63         struct buf **bpp;
  64         int flags;
  65 {
  66         struct m_ext2fs *fs;
  67         struct ext2mount *ump;
  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, *bap, pref;
  73         int osize, nsize, num, i, error;
  74
  75         *bpp = NULL;
  76         if (lbn < 0)
  77                 return (EFBIG);
  78         fs = ip->i_e2fs;
  79         ump = ip->i_ump;
  80
  81         /*
  82          * check if this is a sequential block allocation.
  83          * If so, increment next_alloc fields to allow ext2_blkpref
  84          * to make a good guess
  85          */
  86         if (lbn == ip->i_next_alloc_block + 1) {
  87                 ip->i_next_alloc_block++;
  88                 ip->i_next_alloc_goal++;
  89         }
  90
  91         /*
  92          * The first NDADDR blocks are direct blocks
  93          */
  94         if (lbn < NDADDR) {
  95                 nb = ip->i_db[lbn];
  96                 /* no new block is to be allocated, and no need to expand
  97                    the file */
  98                 if (nb != 0 && ip->i_size >= (lbn + 1) * fs->e2fs_bsize) {
  99                         error = bread(vp, lbn, fs->e2fs_bsize, NOCRED, &bp);
 100                         if (error) {
 101                                 brelse(bp);
 102                                 return (error);
 103                         }
 104                         bp->b_blkno = fsbtodb(fs, nb);
 105                         *bpp = bp;
 106                         return (0);
 107                 }
 108                 if (nb != 0) {
 109                         /*
 110                          * Consider need to reallocate a fragment.
 111                          */
 112                         osize = fragroundup(fs, blkoff(fs, ip->i_size));
 113                         nsize = fragroundup(fs, size);
 114                         if (nsize <= osize) {
 115                                 error = bread(vp, lbn, osize, NOCRED, &bp);
 116                                 if (error) {
 117                                         brelse(bp);
 118                                         return (error);
 119                                 }
 120                                 bp->b_blkno = fsbtodb(fs, nb);
 121                         } else {
 122                         /* Godmar thinks: this shouldn't happen w/o fragments */
 123                                 printf("nsize %d(%d) > osize %d(%d) nb %d\n",
 124                                         (int)nsize, (int)size, (int)osize,
 125                                         (int)ip->i_size, (int)nb);
 126                                 panic(
 127                                     "ext2_balloc: Something is terribly wrong");
 128 /*
 129  * please note there haven't been any changes from here on -
 130  * FFS seems to work.
 131  */
 132                         }
 133                 } else {
 134                         if (ip->i_size < (lbn + 1) * fs->e2fs_bsize)
 135                                 nsize = fragroundup(fs, size);
 136                         else
 137                                 nsize = fs->e2fs_bsize;
 138                         EXT2_LOCK(ump);
 139                         error = ext2_alloc(ip, lbn,
 140                             ext2_blkpref(ip, lbn, (int)lbn, &ip->i_db[0], 0),
 141                             nsize, cred, &newb);
 142                         if (error)
 143                                 return (error);
 144                         bp = getblk(vp, lbn, nsize, 0, 0, 0);
 145                         bp->b_blkno = fsbtodb(fs, newb);
 146                         if (flags & BA_CLRBUF)
 147                                 vfs_bio_clrbuf(bp);
 148                 }
 149                 ip->i_db[lbn] = dbtofsb(fs, bp->b_blkno);
 150                 ip->i_flag |= IN_CHANGE | IN_UPDATE;
 151                 *bpp = bp;
 152                 return (0);
 153         }
 154         /*
 155          * Determine the number of levels of indirection.
 156          */
 157         pref = 0;
 158         if ((error = ext2_getlbns(vp, lbn, indirs, &num)) != 0)
 159                 return(error);
 160 #ifdef DIAGNOSTIC
 161         if (num < 1)
 162                 panic ("ext2_balloc: ext2_getlbns returned indirect block");
 163 #endif
 164         /*
 165          * Fetch the first indirect block allocating if necessary.
 166          */
 167         --num;
 168         nb = ip->i_ib[indirs[0].in_off];
 169         if (nb == 0) {
 170                 EXT2_LOCK(ump);
 171                 pref = ext2_blkpref(ip, lbn, indirs[0].in_off +
 172                                              EXT2_NDIR_BLOCKS, &ip->i_db[0], 0);
 173                 if ((error = ext2_alloc(ip, lbn, pref,
 174                         (int)fs->e2fs_bsize, cred, &newb)))
 175                         return (error);
 176                 nb = newb;
 177                 bp = getblk(vp, indirs[1].in_lbn, fs->e2fs_bsize, 0, 0, 0);
 178                 bp->b_blkno = fsbtodb(fs, newb);
 179                 vfs_bio_clrbuf(bp);
 180                 /*
 181                  * Write synchronously so that indirect blocks
 182                  * never point at garbage.
 183                  */
 184                 if ((error = bwrite(bp)) != 0) {
 185                         ext2_blkfree(ip, nb, fs->e2fs_bsize);
 186                         return (error);
 187                 }
 188                 ip->i_ib[indirs[0].in_off] = newb;
 189                 ip->i_flag |= IN_CHANGE | IN_UPDATE;
 190         }
 191         /*
 192          * Fetch through the indirect blocks, allocating as necessary.
 193          */
 194         for (i = 1;;) {
 195                 error = bread(vp,
 196                     indirs[i].in_lbn, (int)fs->e2fs_bsize, NOCRED, &bp);
 197                 if (error) {
 198                         brelse(bp);
 199                         return (error);
 200                 }
 201                 bap = (int32_t *)bp->b_data;
 202                 nb = bap[indirs[i].in_off];
 203                 if (i == num)
 204                         break;
 205                 i += 1;
 206                 if (nb != 0) {
 207                         bqrelse(bp);
 208                         continue;
 209                 }
 210                 EXT2_LOCK(ump);
 211                 if (pref == 0)
 212                         pref = ext2_blkpref(ip, lbn, indirs[i].in_off, bap,
 213                                                 bp->b_lblkno);
 214                 error =  ext2_alloc(ip, lbn, pref, (int)fs->e2fs_bsize, cred, &newb);
 215                 if (error) {
 216                         brelse(bp);
 217                         return (error);
 218                 }
 219                 nb = newb;
 220                 nbp = getblk(vp, indirs[i].in_lbn, fs->e2fs_bsize, 0, 0, 0);
 221                 nbp->b_blkno = fsbtodb(fs, nb);
 222                 vfs_bio_clrbuf(nbp);
 223                 /*
 224                  * Write synchronously so that indirect blocks
 225                  * never point at garbage.
 226                  */
 227                 if ((error = bwrite(nbp)) != 0) {
 228                         ext2_blkfree(ip, nb, fs->e2fs_bsize);
 229                         EXT2_UNLOCK(ump);
 230                         brelse(bp);
 231                         return (error);
 232                 }
 233                 bap[indirs[i - 1].in_off] = nb;
 234                 /*
 235                  * If required, write synchronously, otherwise use
 236                  * delayed write.
 237                  */
 238                 if (flags & IO_SYNC) {
 239                         bwrite(bp);
 240                 } else {
 241                         if (bp->b_bufsize == fs->e2fs_bsize)
 242                                 bp->b_flags |= B_CLUSTEROK;
 243                         bdwrite(bp);
 244                 }
 245         }
 246         /*
 247          * Get the data block, allocating if necessary.
 248          */
 249         if (nb == 0) {
 250                 EXT2_LOCK(ump);
 251                 pref = ext2_blkpref(ip, lbn, indirs[i].in_off, &bap[0],
 252                                 bp->b_lblkno);
 253                 if ((error = ext2_alloc(ip,
 254                     lbn, pref, (int)fs->e2fs_bsize, cred, &newb)) != 0) {
 255                         brelse(bp);
 256                         return (error);
 257                 }
 258                 nb = newb;
 259                 nbp = getblk(vp, lbn, fs->e2fs_bsize, 0, 0, 0);
 260                 nbp->b_blkno = fsbtodb(fs, nb);
 261                 if (flags & BA_CLRBUF)
 262                         vfs_bio_clrbuf(nbp);
 263                 bap[indirs[i].in_off] = nb;
 264                 /*
 265                  * If required, write synchronously, otherwise use
 266                  * delayed write.
 267                  */
 268                 if (flags & IO_SYNC) {
 269                         bwrite(bp);
 270                 } else {
 271                 if (bp->b_bufsize == fs->e2fs_bsize)
 272                                 bp->b_flags |= B_CLUSTEROK;
 273                         bdwrite(bp);
 274                 }
 275                 *bpp = nbp;
 276                 return (0);
 277         }
 278         brelse(bp);
 279         if (flags & BA_CLRBUF) {
 280                 int seqcount = (flags & BA_SEQMASK) >> BA_SEQSHIFT;
 281                 if (seqcount && (vp->v_mount->mnt_flag & MNT_NOCLUSTERR) == 0) {
 282                         error = cluster_read(vp, ip->i_size, lbn,
 283                             (int)fs->e2fs_bsize, NOCRED,
 284                             MAXBSIZE, seqcount, &nbp);
 285                 } else {
 286                         error = bread(vp, lbn, (int)fs->e2fs_bsize, NOCRED, &nbp);
 287                 }
 288                 if (error) {
 289                         brelse(nbp);
 290                         return (error);
 291                 }
 292         } else {
 293                 nbp = getblk(vp, lbn, fs->e2fs_bsize, 0, 0, 0);
 294                 nbp->b_blkno = fsbtodb(fs, nb);
 295         }
 296         *bpp = nbp;
 297         return (0);
 298 }
 299