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_inode.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  * 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_inode.c 8.5 (Berkeley) 12/30/93
   36  * $FreeBSD: releng/9.2/sys/fs/ext2fs/ext2_inode.c 252008 2013-06-19 20:56:44Z pfg $
   37  */
   38 
   39 #include <sys/param.h>
   40 #include <sys/systm.h>
   41 #include <sys/mount.h>
   42 #include <sys/bio.h>
   43 #include <sys/buf.h>
   44 #include <sys/vnode.h>
   45 #include <sys/malloc.h>
   46 
   47 #include <vm/vm.h>
   48 #include <vm/vm_extern.h>
   49 
   50 #include <fs/ext2fs/inode.h>
   51 #include <fs/ext2fs/ext2_mount.h>
   52 #include <fs/ext2fs/ext2fs.h>
   53 #include <fs/ext2fs/fs.h>
   54 #include <fs/ext2fs/ext2_extern.h>
   55 
   56 static int ext2_indirtrunc(struct inode *, int32_t, int32_t, int32_t, int,
   57             long *);
   58 
   59 /*
   60  * Update the access, modified, and inode change times as specified by the
   61  * IN_ACCESS, IN_UPDATE, and IN_CHANGE flags respectively.  Write the inode
   62  * to disk if the IN_MODIFIED flag is set (it may be set initially, or by
   63  * the timestamp update).  The IN_LAZYMOD flag is set to force a write
   64  * later if not now.  If we write now, then clear both IN_MODIFIED and
   65  * IN_LAZYMOD to reflect the presumably successful write, and if waitfor is
   66  * set, then wait for the write to complete.
   67  */
   68 int
   69 ext2_update(struct vnode *vp, int waitfor)
   70 {
   71         struct m_ext2fs *fs;
   72         struct buf *bp;
   73         struct inode *ip;
   74         int error;
   75 
   76         ASSERT_VOP_ELOCKED(vp, "ext2_update");
   77         ext2_itimes(vp);
   78         ip = VTOI(vp);
   79         if ((ip->i_flag & IN_MODIFIED) == 0 && waitfor == 0)
   80                 return (0);
   81         ip->i_flag &= ~(IN_LAZYACCESS | IN_LAZYMOD | IN_MODIFIED);
   82         fs = ip->i_e2fs;
   83         if(fs->e2fs_ronly)
   84                 return (0);
   85         if ((error = bread(ip->i_devvp,
   86             fsbtodb(fs, ino_to_fsba(fs, ip->i_number)),
   87                 (int)fs->e2fs_bsize, NOCRED, &bp)) != 0) {
   88                 brelse(bp);
   89                 return (error);
   90         }
   91         ext2_i2ei(ip, (struct ext2fs_dinode *)((char *)bp->b_data +
   92             EXT2_INODE_SIZE(fs) * ino_to_fsbo(fs, ip->i_number)));
   93         if (waitfor && !DOINGASYNC(vp))
   94                 return (bwrite(bp));
   95         else {
   96                 bdwrite(bp);
   97                 return (0);
   98         }
   99 }
  100 
  101 #define SINGLE  0       /* index of single indirect block */
  102 #define DOUBLE  1       /* index of double indirect block */
  103 #define TRIPLE  2       /* index of triple indirect block */
  104 /*
  105  * Truncate the inode oip to at most length size, freeing the
  106  * disk blocks.
  107  */
  108 int
  109 ext2_truncate(struct vnode *vp, off_t length, int flags, struct ucred *cred,
  110     struct thread *td)
  111 {
  112         struct vnode *ovp = vp;
  113         int32_t lastblock;
  114         struct inode *oip;
  115         int32_t bn, lbn, lastiblock[NIADDR], indir_lbn[NIADDR];
  116         uint32_t oldblks[NDADDR + NIADDR], newblks[NDADDR + NIADDR];
  117         struct bufobj *bo;
  118         struct m_ext2fs *fs;
  119         struct buf *bp;
  120         int offset, size, level;
  121         long count, nblocks, blocksreleased = 0;
  122         int error, i, allerror;
  123         off_t osize;
  124 
  125         oip = VTOI(ovp);
  126         bo = &ovp->v_bufobj;
  127 
  128         ASSERT_VOP_LOCKED(vp, "ext2_truncate"); 
  129 
  130         if (length < 0)
  131             return (EINVAL);
  132 
  133         if (ovp->v_type == VLNK &&
  134             oip->i_size < ovp->v_mount->mnt_maxsymlinklen) {
  135 #ifdef INVARIANTS
  136                 if (length != 0)
  137                         panic("ext2_truncate: partial truncate of symlink");
  138 #endif
  139                 bzero((char *)&oip->i_shortlink, (u_int)oip->i_size);
  140                 oip->i_size = 0;
  141                 oip->i_flag |= IN_CHANGE | IN_UPDATE;
  142                 return (ext2_update(ovp, 1));
  143         }
  144         if (oip->i_size == length) {
  145                 oip->i_flag |= IN_CHANGE | IN_UPDATE;
  146                 return (ext2_update(ovp, 0));
  147         }
  148         fs = oip->i_e2fs;
  149         osize = oip->i_size;
  150         /*
  151          * Lengthen the size of the file. We must ensure that the
  152          * last byte of the file is allocated. Since the smallest
  153          * value of osize is 0, length will be at least 1.
  154          */
  155         if (osize < length) {
  156                 if (length > oip->i_e2fs->e2fs_maxfilesize)
  157                         return (EFBIG);
  158                 vnode_pager_setsize(ovp, length);
  159                 offset = blkoff(fs, length - 1);
  160                 lbn = lblkno(fs, length - 1);
  161                 flags |= BA_CLRBUF;
  162                 error = ext2_balloc(oip, lbn, offset + 1, cred, &bp, flags);
  163                 if (error) {
  164                         vnode_pager_setsize(vp, osize);
  165                         return (error);
  166                 }
  167                 oip->i_size = length;
  168                 if (bp->b_bufsize == fs->e2fs_bsize)
  169                         bp->b_flags |= B_CLUSTEROK;
  170                 if (flags & IO_SYNC)
  171                         bwrite(bp);
  172                 else if (DOINGASYNC(ovp))
  173                         bdwrite(bp);
  174                 else
  175                         bawrite(bp);
  176                 oip->i_flag |= IN_CHANGE | IN_UPDATE;
  177                 return (ext2_update(ovp, !DOINGASYNC(ovp)));
  178         }
  179         /*
  180          * Shorten the size of the file. If the file is not being
  181          * truncated to a block boundry, the contents of the
  182          * partial block following the end of the file must be
  183          * zero'ed in case it ever become accessible again because
  184          * of subsequent file growth.
  185          */
  186         /* I don't understand the comment above */
  187         offset = blkoff(fs, length);
  188         if (offset == 0) {
  189                 oip->i_size = length;
  190         } else {
  191                 lbn = lblkno(fs, length);
  192                 flags |= BA_CLRBUF;
  193                 error = ext2_balloc(oip, lbn, offset, cred, &bp, flags);
  194                 if (error)
  195                         return (error);
  196                 oip->i_size = length;
  197                 size = blksize(fs, oip, lbn);
  198                 bzero((char *)bp->b_data + offset, (u_int)(size - offset));
  199                 allocbuf(bp, size);
  200                 if (bp->b_bufsize == fs->e2fs_bsize)
  201                         bp->b_flags |= B_CLUSTEROK;
  202                 if (flags & IO_SYNC)
  203                         bwrite(bp);
  204                 else if (DOINGASYNC(ovp))
  205                         bdwrite(bp);
  206                 else
  207                         bawrite(bp);
  208         }
  209         /*
  210          * Calculate index into inode's block list of
  211          * last direct and indirect blocks (if any)
  212          * which we want to keep.  Lastblock is -1 when
  213          * the file is truncated to 0.
  214          */
  215         lastblock = lblkno(fs, length + fs->e2fs_bsize - 1) - 1;
  216         lastiblock[SINGLE] = lastblock - NDADDR;
  217         lastiblock[DOUBLE] = lastiblock[SINGLE] - NINDIR(fs);
  218         lastiblock[TRIPLE] = lastiblock[DOUBLE] - NINDIR(fs) * NINDIR(fs);
  219         nblocks = btodb(fs->e2fs_bsize);
  220         /*
  221          * Update file and block pointers on disk before we start freeing
  222          * blocks.  If we crash before free'ing blocks below, the blocks
  223          * will be returned to the free list.  lastiblock values are also
  224          * normalized to -1 for calls to ext2_indirtrunc below.
  225          */
  226         bcopy((caddr_t)&oip->i_db[0], (caddr_t)oldblks, sizeof(oldblks));
  227         for (level = TRIPLE; level >= SINGLE; level--)
  228                 if (lastiblock[level] < 0) {
  229                         oip->i_ib[level] = 0;
  230                         lastiblock[level] = -1;
  231                 }
  232         for (i = NDADDR - 1; i > lastblock; i--)
  233                 oip->i_db[i] = 0;
  234         oip->i_flag |= IN_CHANGE | IN_UPDATE;
  235         allerror = ext2_update(ovp, !DOINGASYNC(ovp));
  236 
  237         /*
  238          * Having written the new inode to disk, save its new configuration
  239          * and put back the old block pointers long enough to process them.
  240          * Note that we save the new block configuration so we can check it
  241          * when we are done.
  242          */
  243         bcopy((caddr_t)&oip->i_db[0], (caddr_t)newblks, sizeof(newblks));
  244         bcopy((caddr_t)oldblks, (caddr_t)&oip->i_db[0], sizeof(oldblks));
  245         oip->i_size = osize;
  246         error = vtruncbuf(ovp, cred, td, length, (int)fs->e2fs_bsize);
  247         if (error && (allerror == 0))
  248                 allerror = error;
  249         vnode_pager_setsize(ovp, length);
  250         
  251         /*
  252          * Indirect blocks first.
  253          */
  254         indir_lbn[SINGLE] = -NDADDR;
  255         indir_lbn[DOUBLE] = indir_lbn[SINGLE] - NINDIR(fs) - 1;
  256         indir_lbn[TRIPLE] = indir_lbn[DOUBLE] - NINDIR(fs) * NINDIR(fs) - 1;
  257         for (level = TRIPLE; level >= SINGLE; level--) {
  258                 bn = oip->i_ib[level];
  259                 if (bn != 0) {
  260                         error = ext2_indirtrunc(oip, indir_lbn[level],
  261                             fsbtodb(fs, bn), lastiblock[level], level, &count);
  262                         if (error)
  263                                 allerror = error;
  264                         blocksreleased += count;
  265                         if (lastiblock[level] < 0) {
  266                                 oip->i_ib[level] = 0;
  267                                 ext2_blkfree(oip, bn, fs->e2fs_fsize);
  268                                 blocksreleased += nblocks;
  269                         }
  270                 }
  271                 if (lastiblock[level] >= 0)
  272                         goto done;
  273         }
  274 
  275         /*
  276          * All whole direct blocks or frags.
  277          */
  278         for (i = NDADDR - 1; i > lastblock; i--) {
  279                 long bsize;
  280 
  281                 bn = oip->i_db[i];
  282                 if (bn == 0)
  283                         continue;
  284                 oip->i_db[i] = 0;
  285                 bsize = blksize(fs, oip, i);
  286                 ext2_blkfree(oip, bn, bsize);
  287                 blocksreleased += btodb(bsize);
  288         }
  289         if (lastblock < 0)
  290                 goto done;
  291 
  292         /*
  293          * Finally, look for a change in size of the
  294          * last direct block; release any frags.
  295          */
  296         bn = oip->i_db[lastblock];
  297         if (bn != 0) {
  298                 long oldspace, newspace;
  299 
  300                 /*
  301                  * Calculate amount of space we're giving
  302                  * back as old block size minus new block size.
  303                  */
  304                 oldspace = blksize(fs, oip, lastblock);
  305                 oip->i_size = length;
  306                 newspace = blksize(fs, oip, lastblock);
  307                 if (newspace == 0)
  308                         panic("ext2_truncate: newspace");
  309                 if (oldspace - newspace > 0) {
  310                         /*
  311                          * Block number of space to be free'd is
  312                          * the old block # plus the number of frags
  313                          * required for the storage we're keeping.
  314                          */
  315                         bn += numfrags(fs, newspace);
  316                         ext2_blkfree(oip, bn, oldspace - newspace);
  317                         blocksreleased += btodb(oldspace - newspace);
  318                 }
  319         }
  320 done:
  321 #ifdef INVARIANTS
  322         for (level = SINGLE; level <= TRIPLE; level++)
  323                 if (newblks[NDADDR + level] != oip->i_ib[level])
  324                         panic("itrunc1");
  325         for (i = 0; i < NDADDR; i++)
  326                 if (newblks[i] != oip->i_db[i])
  327                         panic("itrunc2");
  328         BO_LOCK(bo);
  329         if (length == 0 && (bo->bo_dirty.bv_cnt != 0 ||
  330             bo->bo_clean.bv_cnt != 0))
  331                 panic("itrunc3");
  332         BO_UNLOCK(bo);
  333 #endif /* INVARIANTS */
  334         /*
  335          * Put back the real size.
  336          */
  337         oip->i_size = length;
  338         if (oip->i_blocks >= blocksreleased)
  339                 oip->i_blocks -= blocksreleased;
  340         else                            /* sanity */
  341                 oip->i_blocks = 0;
  342         oip->i_flag |= IN_CHANGE;
  343         vnode_pager_setsize(ovp, length);
  344         return (allerror);
  345 }
  346 
  347 /*
  348  * Release blocks associated with the inode ip and stored in the indirect
  349  * block bn.  Blocks are free'd in LIFO order up to (but not including)
  350  * lastbn.  If level is greater than SINGLE, the block is an indirect block
  351  * and recursive calls to indirtrunc must be used to cleanse other indirect
  352  * blocks.
  353  *
  354  * NB: triple indirect blocks are untested.
  355  */
  356 
  357 static int
  358 ext2_indirtrunc(struct inode *ip, int32_t lbn, int32_t dbn, int32_t lastbn,
  359     int level, long *countp)
  360 {
  361         struct buf *bp;
  362         struct m_ext2fs *fs = ip->i_e2fs;
  363         struct vnode *vp;
  364         int32_t *bap, *copy, nb, nlbn, last;
  365         long blkcount, factor;
  366         int i, nblocks, blocksreleased = 0;
  367         int error = 0, allerror = 0;
  368 
  369         /*
  370          * Calculate index in current block of last
  371          * block to be kept.  -1 indicates the entire
  372          * block so we need not calculate the index.
  373          */
  374         factor = 1;
  375         for (i = SINGLE; i < level; i++)
  376                 factor *= NINDIR(fs);
  377         last = lastbn;
  378         if (lastbn > 0)
  379                 last /= factor;
  380         nblocks = btodb(fs->e2fs_bsize);
  381         /*
  382          * Get buffer of block pointers, zero those entries corresponding
  383          * to blocks to be free'd, and update on disk copy first.  Since
  384          * double(triple) indirect before single(double) indirect, calls
  385          * to bmap on these blocks will fail.  However, we already have
  386          * the on disk address, so we have to set the b_blkno field
  387          * explicitly instead of letting bread do everything for us.
  388          */
  389         vp = ITOV(ip);
  390         bp = getblk(vp, lbn, (int)fs->e2fs_bsize, 0, 0, 0);
  391         if ((bp->b_flags & (B_DONE | B_DELWRI)) == 0) {
  392                 bp->b_iocmd = BIO_READ;
  393                 if (bp->b_bcount > bp->b_bufsize)
  394                         panic("ext2_indirtrunc: bad buffer size");
  395                 bp->b_blkno = dbn;
  396                 vfs_busy_pages(bp, 0);
  397                 bp->b_iooffset = dbtob(bp->b_blkno);
  398                 bstrategy(bp);
  399                 error = bufwait(bp);
  400         }
  401         if (error) {
  402                 brelse(bp);
  403                 *countp = 0;
  404                 return (error);
  405         }
  406 
  407         bap = (int32_t *)bp->b_data;
  408         copy = malloc(fs->e2fs_bsize, M_TEMP, M_WAITOK);
  409         bcopy((caddr_t)bap, (caddr_t)copy, (u_int)fs->e2fs_bsize);
  410         bzero((caddr_t)&bap[last + 1],
  411           (u_int)(NINDIR(fs) - (last + 1)) * sizeof(int32_t));
  412         if (last == -1)
  413                 bp->b_flags |= B_INVAL;
  414         if (DOINGASYNC(vp)) {
  415                 bdwrite(bp);
  416         } else {
  417                 error = bwrite(bp);
  418                 if (error)
  419                         allerror = error;
  420         }
  421         bap = copy;
  422 
  423         /*
  424          * Recursively free totally unused blocks.
  425          */
  426         for (i = NINDIR(fs) - 1, nlbn = lbn + 1 - i * factor; i > last;
  427             i--, nlbn += factor) {
  428                 nb = bap[i];
  429                 if (nb == 0)
  430                         continue;
  431                 if (level > SINGLE) {
  432                         if ((error = ext2_indirtrunc(ip, nlbn,
  433                             fsbtodb(fs, nb), (int32_t)-1, level - 1, &blkcount)) != 0)
  434                                 allerror = error;
  435                         blocksreleased += blkcount;
  436                 }
  437                 ext2_blkfree(ip, nb, fs->e2fs_bsize);
  438                 blocksreleased += nblocks;
  439         }
  440 
  441         /*
  442          * Recursively free last partial block.
  443          */
  444         if (level > SINGLE && lastbn >= 0) {
  445                 last = lastbn % factor;
  446                 nb = bap[i];
  447                 if (nb != 0) {
  448                         if ((error = ext2_indirtrunc(ip, nlbn, fsbtodb(fs, nb),
  449                             last, level - 1, &blkcount)) != 0)
  450                                 allerror = error;
  451                         blocksreleased += blkcount;
  452                 }
  453         }
  454         free(copy, M_TEMP);
  455         *countp = blocksreleased;
  456         return (allerror);
  457 }
  458 
  459 /*
  460  *      discard preallocated blocks
  461  */
  462 int
  463 ext2_inactive(struct vop_inactive_args *ap)
  464 {
  465         struct vnode *vp = ap->a_vp;
  466         struct inode *ip = VTOI(vp);
  467         struct thread *td = ap->a_td;
  468         int mode, error = 0;
  469 
  470         /*
  471          * Ignore inodes related to stale file handles.
  472          */
  473         if (ip->i_mode == 0)
  474                 goto out;
  475         if (ip->i_nlink <= 0) {
  476                 error = ext2_truncate(vp, (off_t)0, 0, NOCRED, td);
  477                 ip->i_rdev = 0;
  478                 mode = ip->i_mode;
  479                 ip->i_mode = 0;
  480                 ip->i_flag |= IN_CHANGE | IN_UPDATE;
  481                 ext2_vfree(vp, ip->i_number, mode);
  482         }
  483         if (ip->i_flag & (IN_ACCESS | IN_CHANGE | IN_MODIFIED | IN_UPDATE))
  484                 ext2_update(vp, 0);
  485 out:
  486         /*
  487          * If we are done with the inode, reclaim it
  488          * so that it can be reused immediately.
  489          */
  490         if (ip->i_mode == 0)
  491                 vrecycle(vp, td);
  492         return (error);
  493 }
  494 
  495 /*
  496  * Reclaim an inode so that it can be used for other purposes.
  497  */
  498 int
  499 ext2_reclaim(struct vop_reclaim_args *ap)
  500 {
  501         struct inode *ip;
  502         struct vnode *vp = ap->a_vp;
  503 
  504         ip = VTOI(vp);
  505         if (ip->i_flag & IN_LAZYMOD) {
  506                 ip->i_flag |= IN_MODIFIED;
  507                 ext2_update(vp, 0);
  508         }
  509         vfs_hash_remove(vp);
  510         free(vp->v_data, M_EXT2NODE);
  511         vp->v_data = 0;
  512         vnode_destroy_vobject(vp);
  513         return (0);
  514 }

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