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/endian.h>
   44 #include <sys/bio.h>
   45 #include <sys/buf.h>
   46 #include <sys/limits.h>
   47 #include <sys/lock.h>
   48 #include <sys/mount.h>
   49 #include <sys/vnode.h>
   50 
   51 #include <fs/ext2fs/fs.h>
   52 #include <fs/ext2fs/inode.h>
   53 #include <fs/ext2fs/ext2fs.h>
   54 #include <fs/ext2fs/ext2_dinode.h>
   55 #include <fs/ext2fs/ext2_extern.h>
   56 #include <fs/ext2fs/ext2_mount.h>
   57 
   58 static int
   59 ext2_ext_balloc(struct inode *ip, uint32_t lbn, int size,
   60     struct ucred *cred, struct buf **bpp, int flags)
   61 {
   62         struct m_ext2fs *fs;
   63         struct buf *bp = NULL;
   64         struct vnode *vp = ITOV(ip);
   65         daddr_t newblk;
   66         int blks, error, allocated;
   67 
   68         fs = ip->i_e2fs;
   69         blks = howmany(size, fs->e2fs_bsize);
   70 
   71         error = ext4_ext_get_blocks(ip, lbn, blks, cred, NULL, &allocated, &newblk);
   72         if (error)
   73                 return (error);
   74 
   75         if (allocated) {
   76                 bp = getblk(vp, lbn, fs->e2fs_bsize, 0, 0, 0);
   77                 if(!bp)
   78                         return (EIO);
   79         } else {
   80                 error = bread(vp, lbn, fs->e2fs_bsize, NOCRED, &bp);
   81                 if (error) {
   82                         return (error);
   83                 }
   84         }
   85 
   86         bp->b_blkno = fsbtodb(fs, newblk);
   87         if (flags & BA_CLRBUF)
   88                 vfs_bio_clrbuf(bp);
   89 
   90         *bpp = bp;
   91 
   92         return (error);
   93 }
   94 
   95 /*
   96  * Balloc defines the structure of filesystem storage
   97  * by allocating the physical blocks on a device given
   98  * the inode and the logical block number in a file.
   99  */
  100 int
  101 ext2_balloc(struct inode *ip, e2fs_lbn_t lbn, int size, struct ucred *cred,
  102     struct buf **bpp, int flags)
  103 {
  104         struct m_ext2fs *fs;
  105         struct ext2mount *ump;
  106         struct buf *bp, *nbp;
  107         struct vnode *vp = ITOV(ip);
  108         struct indir indirs[EXT2_NIADDR + 2];
  109         e4fs_daddr_t nb, newb;
  110         e2fs_daddr_t *bap, pref;
  111         int num, i, error;
  112 
  113         *bpp = NULL;
  114         if (lbn < 0)
  115                 return (EFBIG);
  116         fs = ip->i_e2fs;
  117         ump = ip->i_ump;
  118 
  119         /*
  120          * check if this is a sequential block allocation.
  121          * If so, increment next_alloc fields to allow ext2_blkpref
  122          * to make a good guess
  123          */
  124         if (lbn == ip->i_next_alloc_block + 1) {
  125                 ip->i_next_alloc_block++;
  126                 ip->i_next_alloc_goal++;
  127         }
  128 
  129         if (ip->i_flag & IN_E4EXTENTS)
  130                 return (ext2_ext_balloc(ip, lbn, size, cred, bpp, flags));
  131 
  132         /*
  133          * The first EXT2_NDADDR blocks are direct blocks
  134          */
  135         if (lbn < EXT2_NDADDR) {
  136                 nb = ip->i_db[lbn];
  137                 /*
  138                  * no new block is to be allocated, and no need to expand
  139                  * the file
  140                  */
  141                 if (nb != 0) {
  142                         error = bread(vp, lbn, fs->e2fs_bsize, NOCRED, &bp);
  143                         if (error) {
  144                                 return (error);
  145                         }
  146                         bp->b_blkno = fsbtodb(fs, nb);
  147                         if (ip->i_size >= (lbn + 1) * fs->e2fs_bsize) {
  148                                 *bpp = bp;
  149                                 return (0);
  150                         }
  151                 } else {
  152                         EXT2_LOCK(ump);
  153                         error = ext2_alloc(ip, lbn,
  154                             ext2_blkpref(ip, lbn, (int)lbn, &ip->i_db[0], 0),
  155                             fs->e2fs_bsize, cred, &newb);
  156                         if (error)
  157                                 return (error);
  158                         /*
  159                          * If the newly allocated block exceeds 32-bit limit,
  160                          * we can not use it in file block maps.
  161                          */
  162                         if (newb > UINT_MAX)
  163                                 return (EFBIG);
  164                         bp = getblk(vp, lbn, fs->e2fs_bsize, 0, 0, 0);
  165                         bp->b_blkno = fsbtodb(fs, newb);
  166                         if (flags & BA_CLRBUF)
  167                                 vfs_bio_clrbuf(bp);
  168                 }
  169                 ip->i_db[lbn] = dbtofsb(fs, bp->b_blkno);
  170                 ip->i_flag |= IN_CHANGE | IN_UPDATE;
  171                 *bpp = bp;
  172                 return (0);
  173         }
  174         /*
  175          * Determine the number of levels of indirection.
  176          */
  177         pref = 0;
  178         if ((error = ext2_getlbns(vp, lbn, indirs, &num)) != 0)
  179                 return (error);
  180 #ifdef INVARIANTS
  181         if (num < 1)
  182                 panic("ext2_balloc: ext2_getlbns returned indirect block");
  183 #endif
  184         /*
  185          * Fetch the first indirect block allocating if necessary.
  186          */
  187         --num;
  188         nb = ip->i_ib[indirs[0].in_off];
  189         if (nb == 0) {
  190                 EXT2_LOCK(ump);
  191                 pref = ext2_blkpref(ip, lbn, indirs[0].in_off +
  192                     EXT2_NDIR_BLOCKS, &ip->i_db[0], 0);
  193                 if ((error = ext2_alloc(ip, lbn, pref, fs->e2fs_bsize, cred,
  194                     &newb)))
  195                         return (error);
  196                 if (newb > UINT_MAX)
  197                         return (EFBIG);
  198                 nb = newb;
  199                 bp = getblk(vp, indirs[1].in_lbn, fs->e2fs_bsize, 0, 0, 0);
  200                 bp->b_blkno = fsbtodb(fs, newb);
  201                 vfs_bio_clrbuf(bp);
  202                 /*
  203                  * Write synchronously so that indirect blocks
  204                  * never point at garbage.
  205                  */
  206                 if ((error = bwrite(bp)) != 0) {
  207                         ext2_blkfree(ip, nb, fs->e2fs_bsize);
  208                         return (error);
  209                 }
  210                 ip->i_ib[indirs[0].in_off] = newb;
  211                 ip->i_flag |= IN_CHANGE | IN_UPDATE;
  212         }
  213         /*
  214          * Fetch through the indirect blocks, allocating as necessary.
  215          */
  216         for (i = 1;;) {
  217                 error = bread(vp,
  218                     indirs[i].in_lbn, (int)fs->e2fs_bsize, NOCRED, &bp);
  219                 if (error) {
  220                         return (error);
  221                 }
  222                 bap = (e2fs_daddr_t *)bp->b_data;
  223                 nb = le32toh(bap[indirs[i].in_off]);
  224                 if (i == num)
  225                         break;
  226                 i += 1;
  227                 if (nb != 0) {
  228                         bqrelse(bp);
  229                         continue;
  230                 }
  231                 EXT2_LOCK(ump);
  232                 if (pref == 0)
  233                         pref = ext2_blkpref(ip, lbn, indirs[i].in_off, bap,
  234                             bp->b_lblkno);
  235                 error = ext2_alloc(ip, lbn, pref, (int)fs->e2fs_bsize, cred, &newb);
  236                 if (error) {
  237                         brelse(bp);
  238                         return (error);
  239                 }
  240                 if (newb > UINT_MAX)
  241                         return (EFBIG);
  242                 nb = newb;
  243                 nbp = getblk(vp, indirs[i].in_lbn, fs->e2fs_bsize, 0, 0, 0);
  244                 nbp->b_blkno = fsbtodb(fs, nb);
  245                 vfs_bio_clrbuf(nbp);
  246                 /*
  247                  * Write synchronously so that indirect blocks
  248                  * never point at garbage.
  249                  */
  250                 if ((error = bwrite(nbp)) != 0) {
  251                         ext2_blkfree(ip, nb, fs->e2fs_bsize);
  252                         brelse(bp);
  253                         return (error);
  254                 }
  255                 bap[indirs[i - 1].in_off] = htole32(nb);
  256                 /*
  257                  * If required, write synchronously, otherwise use
  258                  * delayed write.
  259                  */
  260                 if (flags & IO_SYNC) {
  261                         bwrite(bp);
  262                 } else {
  263                         if (bp->b_bufsize == fs->e2fs_bsize)
  264                                 bp->b_flags |= B_CLUSTEROK;
  265                         bdwrite(bp);
  266                 }
  267         }
  268         /*
  269          * Get the data block, allocating if necessary.
  270          */
  271         if (nb == 0) {
  272                 EXT2_LOCK(ump);
  273                 pref = ext2_blkpref(ip, lbn, indirs[i].in_off, &bap[0],
  274                     bp->b_lblkno);
  275                 if ((error = ext2_alloc(ip,
  276                     lbn, pref, (int)fs->e2fs_bsize, cred, &newb)) != 0) {
  277                         brelse(bp);
  278                         return (error);
  279                 }
  280                 if (newb > UINT_MAX)
  281                         return (EFBIG);
  282                 nb = newb;
  283                 nbp = getblk(vp, lbn, fs->e2fs_bsize, 0, 0, 0);
  284                 nbp->b_blkno = fsbtodb(fs, nb);
  285                 if (flags & BA_CLRBUF)
  286                         vfs_bio_clrbuf(nbp);
  287                 bap[indirs[i].in_off] = htole32(nb);
  288                 /*
  289                  * If required, write synchronously, otherwise use
  290                  * delayed write.
  291                  */
  292                 if (flags & IO_SYNC) {
  293                         bwrite(bp);
  294                 } else {
  295                         if (bp->b_bufsize == fs->e2fs_bsize)
  296                                 bp->b_flags |= B_CLUSTEROK;
  297                         bdwrite(bp);
  298                 }
  299                 *bpp = nbp;
  300                 return (0);
  301         }
  302         brelse(bp);
  303         if (flags & BA_CLRBUF) {
  304                 int seqcount = (flags & BA_SEQMASK) >> BA_SEQSHIFT;
  305 
  306                 if (seqcount && (vp->v_mount->mnt_flag & MNT_NOCLUSTERR) == 0) {
  307                         error = cluster_read(vp, ip->i_size, lbn,
  308                             (int)fs->e2fs_bsize, NOCRED,
  309                             MAXBSIZE, seqcount, 0, &nbp);
  310                 } else {
  311                         error = bread(vp, lbn, (int)fs->e2fs_bsize, NOCRED, &nbp);
  312                 }
  313                 if (error) {
  314                         brelse(nbp);
  315                         return (error);
  316                 }
  317         } else {
  318                 nbp = getblk(vp, lbn, fs->e2fs_bsize, 0, 0, 0);
  319                 nbp->b_blkno = fsbtodb(fs, nb);
  320         }
  321         *bpp = nbp;
  322         return (0);
  323 }

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