The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/fs/ext2fs/ext2_balloc.c

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    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  * SPDX-License-Identifier: BSD-3-Clause
    9  *
   10  * Copyright (c) 1982, 1986, 1989, 1993
   11  *      The Regents of the University of California.  All rights reserved.
   12  *
   13  * Redistribution and use in source and binary forms, with or without
   14  * modification, are permitted provided that the following conditions
   15  * are met:
   16  * 1. Redistributions of source code must retain the above copyright
   17  *    notice, this list of conditions and the following disclaimer.
   18  * 2. Redistributions in binary form must reproduce the above copyright
   19  *    notice, this list of conditions and the following disclaimer in the
   20  *    documentation and/or other materials provided with the distribution.
   21  * 3. Neither the name of the University nor the names of its contributors
   22  *    may be used to endorse or promote products derived from this software
   23  *    without specific prior written permission.
   24  *
   25  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   35  * SUCH DAMAGE.
   36  *
   37  *      @(#)ffs_balloc.c        8.4 (Berkeley) 9/23/93
   38  * $FreeBSD$
   39  */
   40 
   41 #include <sys/param.h>
   42 #include <sys/systm.h>
   43 #include <sys/bio.h>
   44 #include <sys/buf.h>
   45 #include <sys/limits.h>
   46 #include <sys/lock.h>
   47 #include <sys/mount.h>
   48 #include <sys/vnode.h>
   49 
   50 #include <fs/ext2fs/fs.h>
   51 #include <fs/ext2fs/inode.h>
   52 #include <fs/ext2fs/ext2fs.h>
   53 #include <fs/ext2fs/ext2_dinode.h>
   54 #include <fs/ext2fs/ext2_extern.h>
   55 #include <fs/ext2fs/ext2_mount.h>
   56 
   57 static int
   58 ext2_ext_balloc(struct inode *ip, uint32_t lbn, int size,
   59     struct ucred *cred, struct buf **bpp, int flags)
   60 {
   61         struct m_ext2fs *fs;
   62         struct buf *bp = NULL;
   63         struct vnode *vp = ITOV(ip);
   64         daddr_t newblk;
   65         int blks, error, allocated;
   66 
   67         fs = ip->i_e2fs;
   68         blks = howmany(size, fs->e2fs_bsize);
   69 
   70         error = ext4_ext_get_blocks(ip, lbn, blks, cred, NULL, &allocated, &newblk);
   71         if (error)
   72                 return (error);
   73 
   74         if (allocated) {
   75                 bp = getblk(vp, lbn, fs->e2fs_bsize, 0, 0, 0);
   76                 if(!bp)
   77                         return (EIO);
   78         } else {
   79                 error = bread(vp, lbn, fs->e2fs_bsize, NOCRED, &bp);
   80                 if (error) {
   81                         brelse(bp);
   82                         return (error);
   83                 }
   84         }
   85 
   86 
   87         bp->b_blkno = fsbtodb(fs, newblk);
   88         if (flags & BA_CLRBUF)
   89                 vfs_bio_clrbuf(bp);
   90 
   91         *bpp = bp;
   92 
   93         return (error);
   94 }
   95 
   96 /*
   97  * Balloc defines the structure of filesystem storage
   98  * by allocating the physical blocks on a device given
   99  * the inode and the logical block number in a file.
  100  */
  101 int
  102 ext2_balloc(struct inode *ip, e2fs_lbn_t lbn, int size, struct ucred *cred,
  103     struct buf **bpp, int flags)
  104 {
  105         struct m_ext2fs *fs;
  106         struct ext2mount *ump;
  107         struct buf *bp, *nbp;
  108         struct vnode *vp = ITOV(ip);
  109         struct indir indirs[EXT2_NIADDR + 2];
  110         e4fs_daddr_t nb, newb;
  111         e2fs_daddr_t *bap, pref;
  112         int num, i, error;
  113 
  114         *bpp = NULL;
  115         if (lbn < 0)
  116                 return (EFBIG);
  117         fs = ip->i_e2fs;
  118         ump = ip->i_ump;
  119 
  120         /*
  121          * check if this is a sequential block allocation.
  122          * If so, increment next_alloc fields to allow ext2_blkpref
  123          * to make a good guess
  124          */
  125         if (lbn == ip->i_next_alloc_block + 1) {
  126                 ip->i_next_alloc_block++;
  127                 ip->i_next_alloc_goal++;
  128         }
  129 
  130         if (ip->i_flag & IN_E4EXTENTS)
  131                 return (ext2_ext_balloc(ip, lbn, size, cred, bpp, flags));
  132 
  133         /*
  134          * The first EXT2_NDADDR blocks are direct blocks
  135          */
  136         if (lbn < EXT2_NDADDR) {
  137                 nb = ip->i_db[lbn];
  138                 /*
  139                  * no new block is to be allocated, and no need to expand
  140                  * the file
  141                  */
  142                 if (nb != 0) {
  143                         error = bread(vp, lbn, fs->e2fs_bsize, NOCRED, &bp);
  144                         if (error) {
  145                                 brelse(bp);
  146                                 return (error);
  147                         }
  148                         bp->b_blkno = fsbtodb(fs, nb);
  149                         if (ip->i_size >= (lbn + 1) * fs->e2fs_bsize) {
  150                                 *bpp = bp;
  151                                 return (0);
  152                         }
  153                 } else {
  154                         EXT2_LOCK(ump);
  155                         error = ext2_alloc(ip, lbn,
  156                             ext2_blkpref(ip, lbn, (int)lbn, &ip->i_db[0], 0),
  157                             fs->e2fs_bsize, cred, &newb);
  158                         if (error)
  159                                 return (error);
  160                         /*
  161                          * If the newly allocated block exceeds 32-bit limit,
  162                          * we can not use it in file block maps.
  163                          */
  164                         if (newb > UINT_MAX)
  165                                 return (EFBIG);
  166                         bp = getblk(vp, lbn, fs->e2fs_bsize, 0, 0, 0);
  167                         bp->b_blkno = fsbtodb(fs, newb);
  168                         if (flags & BA_CLRBUF)
  169                                 vfs_bio_clrbuf(bp);
  170                 }
  171                 ip->i_db[lbn] = dbtofsb(fs, bp->b_blkno);
  172                 ip->i_flag |= IN_CHANGE | IN_UPDATE;
  173                 *bpp = bp;
  174                 return (0);
  175         }
  176         /*
  177          * Determine the number of levels of indirection.
  178          */
  179         pref = 0;
  180         if ((error = ext2_getlbns(vp, lbn, indirs, &num)) != 0)
  181                 return (error);
  182 #ifdef INVARIANTS
  183         if (num < 1)
  184                 panic("ext2_balloc: ext2_getlbns returned indirect block");
  185 #endif
  186         /*
  187          * Fetch the first indirect block allocating if necessary.
  188          */
  189         --num;
  190         nb = ip->i_ib[indirs[0].in_off];
  191         if (nb == 0) {
  192                 EXT2_LOCK(ump);
  193                 pref = ext2_blkpref(ip, lbn, indirs[0].in_off +
  194                     EXT2_NDIR_BLOCKS, &ip->i_db[0], 0);
  195                 if ((error = ext2_alloc(ip, lbn, pref, fs->e2fs_bsize, cred,
  196                     &newb)))
  197                         return (error);
  198                 if (newb > UINT_MAX)
  199                         return (EFBIG);
  200                 nb = newb;
  201                 bp = getblk(vp, indirs[1].in_lbn, fs->e2fs_bsize, 0, 0, 0);
  202                 bp->b_blkno = fsbtodb(fs, newb);
  203                 vfs_bio_clrbuf(bp);
  204                 /*
  205                  * Write synchronously so that indirect blocks
  206                  * never point at garbage.
  207                  */
  208                 if ((error = bwrite(bp)) != 0) {
  209                         ext2_blkfree(ip, nb, fs->e2fs_bsize);
  210                         return (error);
  211                 }
  212                 ip->i_ib[indirs[0].in_off] = newb;
  213                 ip->i_flag |= IN_CHANGE | IN_UPDATE;
  214         }
  215         /*
  216          * Fetch through the indirect blocks, allocating as necessary.
  217          */
  218         for (i = 1;;) {
  219                 error = bread(vp,
  220                     indirs[i].in_lbn, (int)fs->e2fs_bsize, NOCRED, &bp);
  221                 if (error) {
  222                         brelse(bp);
  223                         return (error);
  224                 }
  225                 bap = (e2fs_daddr_t *)bp->b_data;
  226                 nb = bap[indirs[i].in_off];
  227                 if (i == num)
  228                         break;
  229                 i += 1;
  230                 if (nb != 0) {
  231                         bqrelse(bp);
  232                         continue;
  233                 }
  234                 EXT2_LOCK(ump);
  235                 if (pref == 0)
  236                         pref = ext2_blkpref(ip, lbn, indirs[i].in_off, bap,
  237                             bp->b_lblkno);
  238                 error = ext2_alloc(ip, lbn, pref, (int)fs->e2fs_bsize, cred, &newb);
  239                 if (error) {
  240                         brelse(bp);
  241                         return (error);
  242                 }
  243                 if (newb > UINT_MAX)
  244                         return (EFBIG);
  245                 nb = newb;
  246                 nbp = getblk(vp, indirs[i].in_lbn, fs->e2fs_bsize, 0, 0, 0);
  247                 nbp->b_blkno = fsbtodb(fs, nb);
  248                 vfs_bio_clrbuf(nbp);
  249                 /*
  250                  * Write synchronously so that indirect blocks
  251                  * never point at garbage.
  252                  */
  253                 if ((error = bwrite(nbp)) != 0) {
  254                         ext2_blkfree(ip, nb, fs->e2fs_bsize);
  255                         brelse(bp);
  256                         return (error);
  257                 }
  258                 bap[indirs[i - 1].in_off] = nb;
  259                 /*
  260                  * If required, write synchronously, otherwise use
  261                  * delayed write.
  262                  */
  263                 if (flags & IO_SYNC) {
  264                         bwrite(bp);
  265                 } else {
  266                         if (bp->b_bufsize == fs->e2fs_bsize)
  267                                 bp->b_flags |= B_CLUSTEROK;
  268                         bdwrite(bp);
  269                 }
  270         }
  271         /*
  272          * Get the data block, allocating if necessary.
  273          */
  274         if (nb == 0) {
  275                 EXT2_LOCK(ump);
  276                 pref = ext2_blkpref(ip, lbn, indirs[i].in_off, &bap[0],
  277                     bp->b_lblkno);
  278                 if ((error = ext2_alloc(ip,
  279                     lbn, pref, (int)fs->e2fs_bsize, cred, &newb)) != 0) {
  280                         brelse(bp);
  281                         return (error);
  282                 }
  283                 if (newb > UINT_MAX)
  284                         return (EFBIG);
  285                 nb = newb;
  286                 nbp = getblk(vp, lbn, fs->e2fs_bsize, 0, 0, 0);
  287                 nbp->b_blkno = fsbtodb(fs, nb);
  288                 if (flags & BA_CLRBUF)
  289                         vfs_bio_clrbuf(nbp);
  290                 bap[indirs[i].in_off] = nb;
  291                 /*
  292                  * If required, write synchronously, otherwise use
  293                  * delayed write.
  294                  */
  295                 if (flags & IO_SYNC) {
  296                         bwrite(bp);
  297                 } else {
  298                         if (bp->b_bufsize == fs->e2fs_bsize)
  299                                 bp->b_flags |= B_CLUSTEROK;
  300                         bdwrite(bp);
  301                 }
  302                 *bpp = nbp;
  303                 return (0);
  304         }
  305         brelse(bp);
  306         if (flags & BA_CLRBUF) {
  307                 int seqcount = (flags & BA_SEQMASK) >> BA_SEQSHIFT;
  308 
  309                 if (seqcount && (vp->v_mount->mnt_flag & MNT_NOCLUSTERR) == 0) {
  310                         error = cluster_read(vp, ip->i_size, lbn,
  311                             (int)fs->e2fs_bsize, NOCRED,
  312                             MAXBSIZE, seqcount, 0, &nbp);
  313                 } else {
  314                         error = bread(vp, lbn, (int)fs->e2fs_bsize, NOCRED, &nbp);
  315                 }
  316                 if (error) {
  317                         brelse(nbp);
  318                         return (error);
  319                 }
  320         } else {
  321                 nbp = getblk(vp, lbn, fs->e2fs_bsize, 0, 0, 0);
  322                 nbp->b_blkno = fsbtodb(fs, nb);
  323         }
  324         *bpp = nbp;
  325         return (0);
  326 }

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