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  * $FreeBSD$
   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 #include <sys/rwlock.h>
   47 
   48 #include <vm/vm.h>
   49 #include <vm/vm_extern.h>
   50 
   51 #include <fs/ext2fs/inode.h>
   52 #include <fs/ext2fs/ext2_mount.h>
   53 #include <fs/ext2fs/ext2fs.h>
   54 #include <fs/ext2fs/fs.h>
   55 #include <fs/ext2fs/ext2_extern.h>
   56 
   57 static int ext2_indirtrunc(struct inode *, daddr_t, daddr_t,
   58             daddr_t, int, e4fs_daddr_t *);
   59 
   60 /*
   61  * Update the access, modified, and inode change times as specified by the
   62  * IN_ACCESS, IN_UPDATE, and IN_CHANGE flags respectively.  Write the inode
   63  * to disk if the IN_MODIFIED flag is set (it may be set initially, or by
   64  * the timestamp update).  The IN_LAZYMOD flag is set to force a write
   65  * later if not now.  If we write now, then clear both IN_MODIFIED and
   66  * IN_LAZYMOD to reflect the presumably successful write, and if waitfor is
   67  * set, then wait for the write to complete.
   68  */
   69 int
   70 ext2_update(struct vnode *vp, int waitfor)
   71 {
   72         struct m_ext2fs *fs;
   73         struct buf *bp;
   74         struct inode *ip;
   75         int error;
   76 
   77         ASSERT_VOP_ELOCKED(vp, "ext2_update");
   78         ext2_itimes(vp);
   79         ip = VTOI(vp);
   80         if ((ip->i_flag & IN_MODIFIED) == 0 && waitfor == 0)
   81                 return (0);
   82         ip->i_flag &= ~(IN_LAZYACCESS | IN_LAZYMOD | IN_MODIFIED);
   83         fs = ip->i_e2fs;
   84         if (fs->e2fs_ronly)
   85                 return (0);
   86         if ((error = bread(ip->i_devvp,
   87             fsbtodb(fs, ino_to_fsba(fs, ip->i_number)),
   88             (int)fs->e2fs_bsize, NOCRED, &bp)) != 0) {
   89                 brelse(bp);
   90                 return (error);
   91         }
   92         ext2_i2ei(ip, (struct ext2fs_dinode *)((char *)bp->b_data +
   93             EXT2_INODE_SIZE(fs) * ino_to_fsbo(fs, ip->i_number)));
   94         if (waitfor && !DOINGASYNC(vp))
   95                 return (bwrite(bp));
   96         else {
   97                 bdwrite(bp);
   98                 return (0);
   99         }
  100 }
  101 
  102 #define SINGLE  0       /* index of single indirect block */
  103 #define DOUBLE  1       /* index of double indirect block */
  104 #define TRIPLE  2       /* index of triple indirect block */
  105 /*
  106  * Truncate the inode oip to at most length size, freeing the
  107  * disk blocks.
  108  */
  109 int
  110 ext2_truncate(struct vnode *vp, off_t length, int flags, struct ucred *cred,
  111     struct thread *td)
  112 {
  113         struct vnode *ovp = vp;
  114         int32_t lastblock;
  115         struct inode *oip;
  116         int32_t bn, lbn, lastiblock[NIADDR], indir_lbn[NIADDR];
  117         uint32_t oldblks[NDADDR + NIADDR], newblks[NDADDR + NIADDR];
  118         struct m_ext2fs *fs;
  119         struct buf *bp;
  120         int offset, size, level;
  121         e4fs_daddr_t count, nblocks, blocksreleased = 0;
  122         int error, i, allerror;
  123         off_t osize;
  124 #ifdef INVARIANTS
  125         struct bufobj *bo;
  126 #endif
  127 
  128         oip = VTOI(ovp);
  129 #ifdef INVARIANTS
  130         bo = &ovp->v_bufobj;
  131 #endif
  132 
  133         ASSERT_VOP_LOCKED(vp, "ext2_truncate");
  134 
  135         if (length < 0)
  136                 return (EINVAL);
  137 
  138         if (ovp->v_type == VLNK &&
  139             oip->i_size < ovp->v_mount->mnt_maxsymlinklen) {
  140 #ifdef INVARIANTS
  141                 if (length != 0)
  142                         panic("ext2_truncate: partial truncate of symlink");
  143 #endif
  144                 bzero((char *)&oip->i_shortlink, (u_int)oip->i_size);
  145                 oip->i_size = 0;
  146                 oip->i_flag |= IN_CHANGE | IN_UPDATE;
  147                 return (ext2_update(ovp, 1));
  148         }
  149         if (oip->i_size == length) {
  150                 oip->i_flag |= IN_CHANGE | IN_UPDATE;
  151                 return (ext2_update(ovp, 0));
  152         }
  153         fs = oip->i_e2fs;
  154         osize = oip->i_size;
  155         /*
  156          * Lengthen the size of the file. We must ensure that the
  157          * last byte of the file is allocated. Since the smallest
  158          * value of osize is 0, length will be at least 1.
  159          */
  160         if (osize < length) {
  161                 if (length > oip->i_e2fs->e2fs_maxfilesize)
  162                         return (EFBIG);
  163                 vnode_pager_setsize(ovp, length);
  164                 offset = blkoff(fs, length - 1);
  165                 lbn = lblkno(fs, length - 1);
  166                 flags |= BA_CLRBUF;
  167                 error = ext2_balloc(oip, lbn, offset + 1, cred, &bp, flags);
  168                 if (error) {
  169                         vnode_pager_setsize(vp, osize);
  170                         return (error);
  171                 }
  172                 oip->i_size = length;
  173                 if (bp->b_bufsize == fs->e2fs_bsize)
  174                         bp->b_flags |= B_CLUSTEROK;
  175                 if (flags & IO_SYNC)
  176                         bwrite(bp);
  177                 else if (DOINGASYNC(ovp))
  178                         bdwrite(bp);
  179                 else
  180                         bawrite(bp);
  181                 oip->i_flag |= IN_CHANGE | IN_UPDATE;
  182                 return (ext2_update(ovp, !DOINGASYNC(ovp)));
  183         }
  184         /*
  185          * Shorten the size of the file. If the file is not being
  186          * truncated to a block boundry, the contents of the
  187          * partial block following the end of the file must be
  188          * zero'ed in case it ever become accessible again because
  189          * of subsequent file growth.
  190          */
  191         /* I don't understand the comment above */
  192         offset = blkoff(fs, length);
  193         if (offset == 0) {
  194                 oip->i_size = length;
  195         } else {
  196                 lbn = lblkno(fs, length);
  197                 flags |= BA_CLRBUF;
  198                 error = ext2_balloc(oip, lbn, offset, cred, &bp, flags);
  199                 if (error)
  200                         return (error);
  201                 oip->i_size = length;
  202                 size = blksize(fs, oip, lbn);
  203                 bzero((char *)bp->b_data + offset, (u_int)(size - offset));
  204                 allocbuf(bp, size);
  205                 if (bp->b_bufsize == fs->e2fs_bsize)
  206                         bp->b_flags |= B_CLUSTEROK;
  207                 if (flags & IO_SYNC)
  208                         bwrite(bp);
  209                 else if (DOINGASYNC(ovp))
  210                         bdwrite(bp);
  211                 else
  212                         bawrite(bp);
  213         }
  214         /*
  215          * Calculate index into inode's block list of
  216          * last direct and indirect blocks (if any)
  217          * which we want to keep.  Lastblock is -1 when
  218          * the file is truncated to 0.
  219          */
  220         lastblock = lblkno(fs, length + fs->e2fs_bsize - 1) - 1;
  221         lastiblock[SINGLE] = lastblock - NDADDR;
  222         lastiblock[DOUBLE] = lastiblock[SINGLE] - NINDIR(fs);
  223         lastiblock[TRIPLE] = lastiblock[DOUBLE] - NINDIR(fs) * NINDIR(fs);
  224         nblocks = btodb(fs->e2fs_bsize);
  225         /*
  226          * Update file and block pointers on disk before we start freeing
  227          * blocks.  If we crash before free'ing blocks below, the blocks
  228          * will be returned to the free list.  lastiblock values are also
  229          * normalized to -1 for calls to ext2_indirtrunc below.
  230          */
  231         for (level = TRIPLE; level >= SINGLE; level--) {
  232                 oldblks[NDADDR + level] = oip->i_ib[level];
  233                 if (lastiblock[level] < 0) {
  234                         oip->i_ib[level] = 0;
  235                         lastiblock[level] = -1;
  236                 }
  237         }
  238         for (i = 0; i < NDADDR; i++) {
  239                 oldblks[i] = oip->i_db[i];
  240                 if (i > lastblock)
  241                         oip->i_db[i] = 0;
  242         }
  243         oip->i_flag |= IN_CHANGE | IN_UPDATE;
  244         allerror = ext2_update(ovp, !DOINGASYNC(ovp));
  245 
  246         /*
  247          * Having written the new inode to disk, save its new configuration
  248          * and put back the old block pointers long enough to process them.
  249          * Note that we save the new block configuration so we can check it
  250          * when we are done.
  251          */
  252         for (i = 0; i < NDADDR; i++) {
  253                 newblks[i] = oip->i_db[i];
  254                 oip->i_db[i] = oldblks[i];
  255         }
  256         for (i = 0; i < NIADDR; i++) {
  257                 newblks[NDADDR + i] = oip->i_ib[i];
  258                 oip->i_ib[i] = oldblks[NDADDR + i];
  259         }
  260         oip->i_size = osize;
  261         error = vtruncbuf(ovp, cred, length, (int)fs->e2fs_bsize);
  262         if (error && (allerror == 0))
  263                 allerror = error;
  264         vnode_pager_setsize(ovp, length);
  265 
  266         /*
  267          * Indirect blocks first.
  268          */
  269         indir_lbn[SINGLE] = -NDADDR;
  270         indir_lbn[DOUBLE] = indir_lbn[SINGLE] - NINDIR(fs) - 1;
  271         indir_lbn[TRIPLE] = indir_lbn[DOUBLE] - NINDIR(fs) * NINDIR(fs) - 1;
  272         for (level = TRIPLE; level >= SINGLE; level--) {
  273                 bn = oip->i_ib[level];
  274                 if (bn != 0) {
  275                         error = ext2_indirtrunc(oip, indir_lbn[level],
  276                             fsbtodb(fs, bn), lastiblock[level], level, &count);
  277                         if (error)
  278                                 allerror = error;
  279                         blocksreleased += count;
  280                         if (lastiblock[level] < 0) {
  281                                 oip->i_ib[level] = 0;
  282                                 ext2_blkfree(oip, bn, fs->e2fs_fsize);
  283                                 blocksreleased += nblocks;
  284                         }
  285                 }
  286                 if (lastiblock[level] >= 0)
  287                         goto done;
  288         }
  289 
  290         /*
  291          * All whole direct blocks or frags.
  292          */
  293         for (i = NDADDR - 1; i > lastblock; i--) {
  294                 long bsize;
  295 
  296                 bn = oip->i_db[i];
  297                 if (bn == 0)
  298                         continue;
  299                 oip->i_db[i] = 0;
  300                 bsize = blksize(fs, oip, i);
  301                 ext2_blkfree(oip, bn, bsize);
  302                 blocksreleased += btodb(bsize);
  303         }
  304         if (lastblock < 0)
  305                 goto done;
  306 
  307         /*
  308          * Finally, look for a change in size of the
  309          * last direct block; release any frags.
  310          */
  311         bn = oip->i_db[lastblock];
  312         if (bn != 0) {
  313                 long oldspace, newspace;
  314 
  315                 /*
  316                  * Calculate amount of space we're giving
  317                  * back as old block size minus new block size.
  318                  */
  319                 oldspace = blksize(fs, oip, lastblock);
  320                 oip->i_size = length;
  321                 newspace = blksize(fs, oip, lastblock);
  322                 if (newspace == 0)
  323                         panic("ext2_truncate: newspace");
  324                 if (oldspace - newspace > 0) {
  325                         /*
  326                          * Block number of space to be free'd is
  327                          * the old block # plus the number of frags
  328                          * required for the storage we're keeping.
  329                          */
  330                         bn += numfrags(fs, newspace);
  331                         ext2_blkfree(oip, bn, oldspace - newspace);
  332                         blocksreleased += btodb(oldspace - newspace);
  333                 }
  334         }
  335 done:
  336 #ifdef INVARIANTS
  337         for (level = SINGLE; level <= TRIPLE; level++)
  338                 if (newblks[NDADDR + level] != oip->i_ib[level])
  339                         panic("itrunc1");
  340         for (i = 0; i < NDADDR; i++)
  341                 if (newblks[i] != oip->i_db[i])
  342                         panic("itrunc2");
  343         BO_LOCK(bo);
  344         if (length == 0 && (bo->bo_dirty.bv_cnt != 0 ||
  345             bo->bo_clean.bv_cnt != 0))
  346                 panic("itrunc3");
  347         BO_UNLOCK(bo);
  348 #endif  /* INVARIANTS */
  349         /*
  350          * Put back the real size.
  351          */
  352         oip->i_size = length;
  353         if (oip->i_blocks >= blocksreleased)
  354                 oip->i_blocks -= blocksreleased;
  355         else                            /* sanity */
  356                 oip->i_blocks = 0;
  357         oip->i_flag |= IN_CHANGE;
  358         vnode_pager_setsize(ovp, length);
  359         return (allerror);
  360 }
  361 
  362 /*
  363  * Release blocks associated with the inode ip and stored in the indirect
  364  * block bn.  Blocks are free'd in LIFO order up to (but not including)
  365  * lastbn.  If level is greater than SINGLE, the block is an indirect block
  366  * and recursive calls to indirtrunc must be used to cleanse other indirect
  367  * blocks.
  368  *
  369  * NB: triple indirect blocks are untested.
  370  */
  371 
  372 static int
  373 ext2_indirtrunc(struct inode *ip, daddr_t lbn, daddr_t dbn,
  374     daddr_t lastbn, int level, e4fs_daddr_t *countp)
  375 {
  376         struct buf *bp;
  377         struct m_ext2fs *fs = ip->i_e2fs;
  378         struct vnode *vp;
  379         e2fs_daddr_t *bap, *copy;
  380         int i, nblocks, error = 0, allerror = 0;
  381         e2fs_lbn_t nb, nlbn, last;
  382         e4fs_daddr_t blkcount, factor, blocksreleased = 0;
  383 
  384         /*
  385          * Calculate index in current block of last
  386          * block to be kept.  -1 indicates the entire
  387          * block so we need not calculate the index.
  388          */
  389         factor = 1;
  390         for (i = SINGLE; i < level; i++)
  391                 factor *= NINDIR(fs);
  392         last = lastbn;
  393         if (lastbn > 0)
  394                 last /= factor;
  395         nblocks = btodb(fs->e2fs_bsize);
  396         /*
  397          * Get buffer of block pointers, zero those entries corresponding
  398          * to blocks to be free'd, and update on disk copy first.  Since
  399          * double(triple) indirect before single(double) indirect, calls
  400          * to bmap on these blocks will fail.  However, we already have
  401          * the on disk address, so we have to set the b_blkno field
  402          * explicitly instead of letting bread do everything for us.
  403          */
  404         vp = ITOV(ip);
  405         bp = getblk(vp, lbn, (int)fs->e2fs_bsize, 0, 0, 0);
  406         if ((bp->b_flags & (B_DONE | B_DELWRI)) == 0) {
  407                 bp->b_iocmd = BIO_READ;
  408                 if (bp->b_bcount > bp->b_bufsize)
  409                         panic("ext2_indirtrunc: bad buffer size");
  410                 bp->b_blkno = dbn;
  411                 vfs_busy_pages(bp, 0);
  412                 bp->b_iooffset = dbtob(bp->b_blkno);
  413                 bstrategy(bp);
  414                 error = bufwait(bp);
  415         }
  416         if (error) {
  417                 brelse(bp);
  418                 *countp = 0;
  419                 return (error);
  420         }
  421         bap = (e2fs_daddr_t *)bp->b_data;
  422         copy = malloc(fs->e2fs_bsize, M_TEMP, M_WAITOK);
  423         bcopy((caddr_t)bap, (caddr_t)copy, (u_int)fs->e2fs_bsize);
  424         bzero((caddr_t)&bap[last + 1],
  425             (NINDIR(fs) - (last + 1)) * sizeof(e2fs_daddr_t));
  426         if (last == -1)
  427                 bp->b_flags |= B_INVAL;
  428         if (DOINGASYNC(vp)) {
  429                 bdwrite(bp);
  430         } else {
  431                 error = bwrite(bp);
  432                 if (error)
  433                         allerror = error;
  434         }
  435         bap = copy;
  436 
  437         /*
  438          * Recursively free totally unused blocks.
  439          */
  440         for (i = NINDIR(fs) - 1, nlbn = lbn + 1 - i * factor; i > last;
  441             i--, nlbn += factor) {
  442                 nb = bap[i];
  443                 if (nb == 0)
  444                         continue;
  445                 if (level > SINGLE) {
  446                         if ((error = ext2_indirtrunc(ip, nlbn,
  447                             fsbtodb(fs, nb), (int32_t)-1, level - 1, &blkcount)) != 0)
  448                                 allerror = error;
  449                         blocksreleased += blkcount;
  450                 }
  451                 ext2_blkfree(ip, nb, fs->e2fs_bsize);
  452                 blocksreleased += nblocks;
  453         }
  454 
  455         /*
  456          * Recursively free last partial block.
  457          */
  458         if (level > SINGLE && lastbn >= 0) {
  459                 last = lastbn % factor;
  460                 nb = bap[i];
  461                 if (nb != 0) {
  462                         if ((error = ext2_indirtrunc(ip, nlbn, fsbtodb(fs, nb),
  463                             last, level - 1, &blkcount)) != 0)
  464                                 allerror = error;
  465                         blocksreleased += blkcount;
  466                 }
  467         }
  468         free(copy, M_TEMP);
  469         *countp = blocksreleased;
  470         return (allerror);
  471 }
  472 
  473 /*
  474  *      discard preallocated blocks
  475  */
  476 int
  477 ext2_inactive(struct vop_inactive_args *ap)
  478 {
  479         struct vnode *vp = ap->a_vp;
  480         struct inode *ip = VTOI(vp);
  481         struct thread *td = ap->a_td;
  482         int mode, error = 0;
  483 
  484         /*
  485          * Ignore inodes related to stale file handles.
  486          */
  487         if (ip->i_mode == 0)
  488                 goto out;
  489         if (ip->i_nlink <= 0) {
  490                 error = ext2_truncate(vp, (off_t)0, 0, NOCRED, td);
  491                 ip->i_rdev = 0;
  492                 mode = ip->i_mode;
  493                 ip->i_mode = 0;
  494                 ip->i_flag |= IN_CHANGE | IN_UPDATE;
  495                 ext2_vfree(vp, ip->i_number, mode);
  496         }
  497         if (ip->i_flag & (IN_ACCESS | IN_CHANGE | IN_MODIFIED | IN_UPDATE))
  498                 ext2_update(vp, 0);
  499 out:
  500         /*
  501          * If we are done with the inode, reclaim it
  502          * so that it can be reused immediately.
  503          */
  504         if (ip->i_mode == 0)
  505                 vrecycle(vp);
  506         return (error);
  507 }
  508 
  509 /*
  510  * Reclaim an inode so that it can be used for other purposes.
  511  */
  512 int
  513 ext2_reclaim(struct vop_reclaim_args *ap)
  514 {
  515         struct inode *ip;
  516         struct vnode *vp = ap->a_vp;
  517 
  518         ip = VTOI(vp);
  519         if (ip->i_flag & IN_LAZYMOD) {
  520                 ip->i_flag |= IN_MODIFIED;
  521                 ext2_update(vp, 0);
  522         }
  523         vfs_hash_remove(vp);
  524         free(vp->v_data, M_EXT2NODE);
  525         vp->v_data = 0;
  526         vnode_destroy_vobject(vp);
  527         return (0);
  528 }

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