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/fs.h>
  48 #include <fs/ext2fs/inode.h>
  49 #include <fs/ext2fs/ext2fs.h>
  50 #include <fs/ext2fs/ext2_dinode.h>
  51 #include <fs/ext2fs/ext2_extern.h>
  52 #include <fs/ext2fs/ext2_mount.h>
  53
  54 /*
  55  * Balloc defines the structure of filesystem storage
  56  * by allocating the physical blocks on a device given
  57  * the inode and the logical block number in a file.
  58  */
  59 int
  60 ext2_balloc(struct inode *ip, e2fs_lbn_t lbn, int size, struct ucred *cred,
  61     struct buf **bpp, int flags)
  62 {
  63         struct m_ext2fs *fs;
  64         struct ext2mount *ump;
  65         struct buf *bp, *nbp;
  66         struct vnode *vp = ITOV(ip);
  67         struct indir indirs[NIADDR + 2];
  68         e4fs_daddr_t nb, newb;
  69         e2fs_daddr_t *bap, pref;
  70         int osize, nsize, num, i, error;
  71
  72         *bpp = NULL;
  73         if (lbn < 0)
  74                 return (EFBIG);
  75         fs = ip->i_e2fs;
  76         ump = ip->i_ump;
  77
  78         /*
  79          * check if this is a sequential block allocation.
  80          * If so, increment next_alloc fields to allow ext2_blkpref
  81          * to make a good guess
  82          */
  83         if (lbn == ip->i_next_alloc_block + 1) {
  84                 ip->i_next_alloc_block++;
  85                 ip->i_next_alloc_goal++;
  86         }
  87
  88         /*
  89          * The first NDADDR blocks are direct blocks
  90          */
  91         if (lbn < NDADDR) {
  92                 nb = ip->i_db[lbn];
  93                 /* no new block is to be allocated, and no need to expand
  94                    the file */
  95                 if (nb != 0 && ip->i_size >= (lbn + 1) * fs->e2fs_bsize) {
  96                         error = bread(vp, lbn, fs->e2fs_bsize, NOCRED, &bp);
  97                         if (error) {
  98                                 brelse(bp);
  99                                 return (error);
 100                         }
 101                         bp->b_blkno = fsbtodb(fs, nb);
 102                         *bpp = bp;
 103                         return (0);
 104                 }
 105                 if (nb != 0) {
 106                         /*
 107                          * Consider need to reallocate a fragment.
 108                          */
 109                         osize = fragroundup(fs, blkoff(fs, ip->i_size));
 110                         nsize = fragroundup(fs, size);
 111                         if (nsize <= osize) {
 112                                 error = bread(vp, lbn, osize, NOCRED, &bp);
 113                                 if (error) {
 114                                         brelse(bp);
 115                                         return (error);
 116                                 }
 117                                 bp->b_blkno = fsbtodb(fs, nb);
 118                         } else {
 119                         /* Godmar thinks: this shouldn't happen w/o fragments */
 120                                 printf("nsize %d(%d) > osize %d(%d) nb %d\n",
 121                                         (int)nsize, (int)size, (int)osize,
 122                                         (int)ip->i_size, (int)nb);
 123                                 panic(
 124                                     "ext2_balloc: Something is terribly wrong");
 125 /*
 126  * please note there haven't been any changes from here on -
 127  * FFS seems to work.
 128  */
 129                         }
 130                 } else {
 131                         if (ip->i_size < (lbn + 1) * fs->e2fs_bsize)
 132                                 nsize = fragroundup(fs, size);
 133                         else
 134                                 nsize = fs->e2fs_bsize;
 135                         EXT2_LOCK(ump);
 136                         error = ext2_alloc(ip, lbn,
 137                             ext2_blkpref(ip, lbn, (int)lbn, &ip->i_db[0], 0),
 138                             nsize, cred, &newb);
 139                         if (error)
 140                                 return (error);
 141                         bp = getblk(vp, lbn, nsize, 0, 0, 0);
 142                         bp->b_blkno = fsbtodb(fs, newb);
 143                         if (flags & BA_CLRBUF)
 144                                 vfs_bio_clrbuf(bp);
 145                 }
 146                 ip->i_db[lbn] = dbtofsb(fs, bp->b_blkno);
 147                 ip->i_flag |= IN_CHANGE | IN_UPDATE;
 148                 *bpp = bp;
 149                 return (0);
 150         }
 151         /*
 152          * Determine the number of levels of indirection.
 153          */
 154         pref = 0;
 155         if ((error = ext2_getlbns(vp, lbn, indirs, &num)) != 0)
 156                 return (error);
 157 #ifdef INVARIANTS
 158         if (num < 1)
 159                 panic ("ext2_balloc: ext2_getlbns returned indirect block");
 160 #endif
 161         /*
 162          * Fetch the first indirect block allocating if necessary.
 163          */
 164         --num;
 165         nb = ip->i_ib[indirs[0].in_off];
 166         if (nb == 0) {
 167                 EXT2_LOCK(ump);
 168                 pref = ext2_blkpref(ip, lbn, indirs[0].in_off +
 169                                              EXT2_NDIR_BLOCKS, &ip->i_db[0], 0);
 170                 if ((error = ext2_alloc(ip, lbn, pref, fs->e2fs_bsize, cred,
 171                         &newb)))
 172                         return (error);
 173                 nb = newb;
 174                 bp = getblk(vp, indirs[1].in_lbn, fs->e2fs_bsize, 0, 0, 0);
 175                 bp->b_blkno = fsbtodb(fs, newb);
 176                 vfs_bio_clrbuf(bp);
 177                 /*
 178                  * Write synchronously so that indirect blocks
 179                  * never point at garbage.
 180                  */
 181                 if ((error = bwrite(bp)) != 0) {
 182                         ext2_blkfree(ip, nb, fs->e2fs_bsize);
 183                         return (error);
 184                 }
 185                 ip->i_ib[indirs[0].in_off] = newb;
 186                 ip->i_flag |= IN_CHANGE | IN_UPDATE;
 187         }
 188         /*
 189          * Fetch through the indirect blocks, allocating as necessary.
 190          */
 191         for (i = 1;;) {
 192                 error = bread(vp,
 193                     indirs[i].in_lbn, (int)fs->e2fs_bsize, NOCRED, &bp);
 194                 if (error) {
 195                         brelse(bp);
 196                         return (error);
 197                 }
 198                 bap = (e2fs_daddr_t *)bp->b_data;
 199                 nb = bap[indirs[i].in_off];
 200                 if (i == num)
 201                         break;
 202                 i += 1;
 203                 if (nb != 0) {
 204                         bqrelse(bp);
 205                         continue;
 206                 }
 207                 EXT2_LOCK(ump);
 208                 if (pref == 0)
 209                         pref = ext2_blkpref(ip, lbn, indirs[i].in_off, bap,
 210                                                 bp->b_lblkno);
 211                 error =  ext2_alloc(ip, lbn, pref, (int)fs->e2fs_bsize, cred, &newb);
 212                 if (error) {
 213                         brelse(bp);
 214                         return (error);
 215                 }
 216                 nb = newb;
 217                 nbp = getblk(vp, indirs[i].in_lbn, fs->e2fs_bsize, 0, 0, 0);
 218                 nbp->b_blkno = fsbtodb(fs, nb);
 219                 vfs_bio_clrbuf(nbp);
 220                 /*
 221                  * Write synchronously so that indirect blocks
 222                  * never point at garbage.
 223                  */
 224                 if ((error = bwrite(nbp)) != 0) {
 225                         ext2_blkfree(ip, nb, fs->e2fs_bsize);
 226                         EXT2_UNLOCK(ump);
 227                         brelse(bp);
 228                         return (error);
 229                 }
 230                 bap[indirs[i - 1].in_off] = nb;
 231                 /*
 232                  * If required, write synchronously, otherwise use
 233                  * delayed write.
 234                  */
 235                 if (flags & IO_SYNC) {
 236                         bwrite(bp);
 237                 } else {
 238                         if (bp->b_bufsize == fs->e2fs_bsize)
 239                                 bp->b_flags |= B_CLUSTEROK;
 240                         bdwrite(bp);
 241                 }
 242         }
 243         /*
 244          * Get the data block, allocating if necessary.
 245          */
 246         if (nb == 0) {
 247                 EXT2_LOCK(ump);
 248                 pref = ext2_blkpref(ip, lbn, indirs[i].in_off, &bap[0],
 249                                 bp->b_lblkno);
 250                 if ((error = ext2_alloc(ip,
 251                     lbn, pref, (int)fs->e2fs_bsize, cred, &newb)) != 0) {
 252                         brelse(bp);
 253                         return (error);
 254                 }
 255                 nb = newb;
 256                 nbp = getblk(vp, lbn, fs->e2fs_bsize, 0, 0, 0);
 257                 nbp->b_blkno = fsbtodb(fs, nb);
 258                 if (flags & BA_CLRBUF)
 259                         vfs_bio_clrbuf(nbp);
 260                 bap[indirs[i].in_off] = nb;
 261                 /*
 262                  * If required, write synchronously, otherwise use
 263                  * delayed write.
 264                  */
 265                 if (flags & IO_SYNC) {
 266                         bwrite(bp);
 267                 } else {
 268                 if (bp->b_bufsize == fs->e2fs_bsize)
 269                                 bp->b_flags |= B_CLUSTEROK;
 270                         bdwrite(bp);
 271                 }
 272                 *bpp = nbp;
 273                 return (0);
 274         }
 275         brelse(bp);
 276         if (flags & BA_CLRBUF) {
 277                 int seqcount = (flags & BA_SEQMASK) >> BA_SEQSHIFT;
 278                 if (seqcount && (vp->v_mount->mnt_flag & MNT_NOCLUSTERR) == 0) {
 279                         error = cluster_read(vp, ip->i_size, lbn,
 280                             (int)fs->e2fs_bsize, NOCRED,
 281                             MAXBSIZE, seqcount, 0, &nbp);
 282                 } else {
 283                         error = bread(vp, lbn, (int)fs->e2fs_bsize, NOCRED, &nbp);
 284                 }
 285                 if (error) {
 286                         brelse(nbp);
 287                         return (error);
 288                 }
 289         } else {
 290                 nbp = getblk(vp, lbn, fs->e2fs_bsize, 0, 0, 0);
 291                 nbp->b_blkno = fsbtodb(fs, nb);
 292         }
 293         *bpp = nbp;
 294         return (0);
 295 }
 296