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/11.2/sys/fs/ext2fs/ext2_inode.c 331722 2018-03-29 02:50:57Z eadler $
   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 #include <fs/ext2fs/ext2_extattr.h>
   57 
   58 static int ext2_indirtrunc(struct inode *, daddr_t, daddr_t,
   59             daddr_t, int, e4fs_daddr_t *);
   60 
   61 /*
   62  * Update the access, modified, and inode change times as specified by the
   63  * IN_ACCESS, IN_UPDATE, and IN_CHANGE flags respectively.  Write the inode
   64  * to disk if the IN_MODIFIED flag is set (it may be set initially, or by
   65  * the timestamp update).  The IN_LAZYMOD flag is set to force a write
   66  * later if not now.  If we write now, then clear both IN_MODIFIED and
   67  * IN_LAZYMOD to reflect the presumably successful write, and if waitfor is
   68  * set, then wait for the write to complete.
   69  */
   70 int
   71 ext2_update(struct vnode *vp, int waitfor)
   72 {
   73         struct m_ext2fs *fs;
   74         struct buf *bp;
   75         struct inode *ip;
   76         int error;
   77 
   78         ASSERT_VOP_ELOCKED(vp, "ext2_update");
   79         ext2_itimes(vp);
   80         ip = VTOI(vp);
   81         if ((ip->i_flag & IN_MODIFIED) == 0 && waitfor == 0)
   82                 return (0);
   83         ip->i_flag &= ~(IN_LAZYACCESS | IN_LAZYMOD | IN_MODIFIED);
   84         fs = ip->i_e2fs;
   85         if (fs->e2fs_ronly)
   86                 return (0);
   87         if ((error = bread(ip->i_devvp,
   88             fsbtodb(fs, ino_to_fsba(fs, ip->i_number)),
   89             (int)fs->e2fs_bsize, NOCRED, &bp)) != 0) {
   90                 brelse(bp);
   91                 return (error);
   92         }
   93         error = ext2_i2ei(ip, (struct ext2fs_dinode *)((char *)bp->b_data +
   94             EXT2_INODE_SIZE(fs) * ino_to_fsbo(fs, ip->i_number)));
   95         if (error) {
   96                 brelse(bp);
   97                 return (error);
   98         }
   99         if (waitfor && !DOINGASYNC(vp))
  100                 return (bwrite(bp));
  101         else {
  102                 bdwrite(bp);
  103                 return (0);
  104         }
  105 }
  106 
  107 #define SINGLE  0       /* index of single indirect block */
  108 #define DOUBLE  1       /* index of double indirect block */
  109 #define TRIPLE  2       /* index of triple indirect block */
  110 /*
  111  * Truncate the inode oip to at most length size, freeing the
  112  * disk blocks.
  113  */
  114 int
  115 ext2_truncate(struct vnode *vp, off_t length, int flags, struct ucred *cred,
  116     struct thread *td)
  117 {
  118         struct vnode *ovp = vp;
  119         int32_t lastblock;
  120         struct inode *oip;
  121         int32_t bn, lbn, lastiblock[NIADDR], indir_lbn[NIADDR];
  122         uint32_t oldblks[NDADDR + NIADDR], newblks[NDADDR + NIADDR];
  123         struct m_ext2fs *fs;
  124         struct buf *bp;
  125         int offset, size, level;
  126         e4fs_daddr_t count, nblocks, blocksreleased = 0;
  127         int error, i, allerror;
  128         off_t osize;
  129 #ifdef INVARIANTS
  130         struct bufobj *bo;
  131 #endif
  132 
  133         oip = VTOI(ovp);
  134 #ifdef INVARIANTS
  135         bo = &ovp->v_bufobj;
  136 #endif
  137 
  138         ASSERT_VOP_LOCKED(vp, "ext2_truncate");
  139 
  140         if (length < 0)
  141                 return (EINVAL);
  142 
  143         if (ovp->v_type == VLNK &&
  144             oip->i_size < ovp->v_mount->mnt_maxsymlinklen) {
  145 #ifdef INVARIANTS
  146                 if (length != 0)
  147                         panic("ext2_truncate: partial truncate of symlink");
  148 #endif
  149                 bzero((char *)&oip->i_shortlink, (u_int)oip->i_size);
  150                 oip->i_size = 0;
  151                 oip->i_flag |= IN_CHANGE | IN_UPDATE;
  152                 return (ext2_update(ovp, 1));
  153         }
  154         if (oip->i_size == length) {
  155                 oip->i_flag |= IN_CHANGE | IN_UPDATE;
  156                 return (ext2_update(ovp, 0));
  157         }
  158         fs = oip->i_e2fs;
  159         osize = oip->i_size;
  160         /*
  161          * Lengthen the size of the file. We must ensure that the
  162          * last byte of the file is allocated. Since the smallest
  163          * value of osize is 0, length will be at least 1.
  164          */
  165         if (osize < length) {
  166                 if (length > oip->i_e2fs->e2fs_maxfilesize)
  167                         return (EFBIG);
  168                 vnode_pager_setsize(ovp, length);
  169                 offset = blkoff(fs, length - 1);
  170                 lbn = lblkno(fs, length - 1);
  171                 flags |= BA_CLRBUF;
  172                 error = ext2_balloc(oip, lbn, offset + 1, cred, &bp, flags);
  173                 if (error) {
  174                         vnode_pager_setsize(vp, osize);
  175                         return (error);
  176                 }
  177                 oip->i_size = length;
  178                 if (bp->b_bufsize == fs->e2fs_bsize)
  179                         bp->b_flags |= B_CLUSTEROK;
  180                 if (flags & IO_SYNC)
  181                         bwrite(bp);
  182                 else if (DOINGASYNC(ovp))
  183                         bdwrite(bp);
  184                 else
  185                         bawrite(bp);
  186                 oip->i_flag |= IN_CHANGE | IN_UPDATE;
  187                 return (ext2_update(ovp, !DOINGASYNC(ovp)));
  188         }
  189         /*
  190          * Shorten the size of the file. If the file is not being
  191          * truncated to a block boundary, the contents of the
  192          * partial block following the end of the file must be
  193          * zero'ed in case it ever become accessible again because
  194          * of subsequent file growth.
  195          */
  196         /* I don't understand the comment above */
  197         offset = blkoff(fs, length);
  198         if (offset == 0) {
  199                 oip->i_size = length;
  200         } else {
  201                 lbn = lblkno(fs, length);
  202                 flags |= BA_CLRBUF;
  203                 error = ext2_balloc(oip, lbn, offset, cred, &bp, flags);
  204                 if (error)
  205                         return (error);
  206                 oip->i_size = length;
  207                 size = blksize(fs, oip, lbn);
  208                 bzero((char *)bp->b_data + offset, (u_int)(size - offset));
  209                 allocbuf(bp, size);
  210                 if (bp->b_bufsize == fs->e2fs_bsize)
  211                         bp->b_flags |= B_CLUSTEROK;
  212                 if (flags & IO_SYNC)
  213                         bwrite(bp);
  214                 else if (DOINGASYNC(ovp))
  215                         bdwrite(bp);
  216                 else
  217                         bawrite(bp);
  218         }
  219         /*
  220          * Calculate index into inode's block list of
  221          * last direct and indirect blocks (if any)
  222          * which we want to keep.  Lastblock is -1 when
  223          * the file is truncated to 0.
  224          */
  225         lastblock = lblkno(fs, length + fs->e2fs_bsize - 1) - 1;
  226         lastiblock[SINGLE] = lastblock - NDADDR;
  227         lastiblock[DOUBLE] = lastiblock[SINGLE] - NINDIR(fs);
  228         lastiblock[TRIPLE] = lastiblock[DOUBLE] - NINDIR(fs) * NINDIR(fs);
  229         nblocks = btodb(fs->e2fs_bsize);
  230         /*
  231          * Update file and block pointers on disk before we start freeing
  232          * blocks.  If we crash before free'ing blocks below, the blocks
  233          * will be returned to the free list.  lastiblock values are also
  234          * normalized to -1 for calls to ext2_indirtrunc below.
  235          */
  236         for (level = TRIPLE; level >= SINGLE; level--) {
  237                 oldblks[NDADDR + level] = oip->i_ib[level];
  238                 if (lastiblock[level] < 0) {
  239                         oip->i_ib[level] = 0;
  240                         lastiblock[level] = -1;
  241                 }
  242         }
  243         for (i = 0; i < NDADDR; i++) {
  244                 oldblks[i] = oip->i_db[i];
  245                 if (i > lastblock)
  246                         oip->i_db[i] = 0;
  247         }
  248         oip->i_flag |= IN_CHANGE | IN_UPDATE;
  249         allerror = ext2_update(ovp, !DOINGASYNC(ovp));
  250 
  251         /*
  252          * Having written the new inode to disk, save its new configuration
  253          * and put back the old block pointers long enough to process them.
  254          * Note that we save the new block configuration so we can check it
  255          * when we are done.
  256          */
  257         for (i = 0; i < NDADDR; i++) {
  258                 newblks[i] = oip->i_db[i];
  259                 oip->i_db[i] = oldblks[i];
  260         }
  261         for (i = 0; i < NIADDR; i++) {
  262                 newblks[NDADDR + i] = oip->i_ib[i];
  263                 oip->i_ib[i] = oldblks[NDADDR + i];
  264         }
  265         oip->i_size = osize;
  266         error = vtruncbuf(ovp, cred, length, (int)fs->e2fs_bsize);
  267         if (error && (allerror == 0))
  268                 allerror = error;
  269         vnode_pager_setsize(ovp, length);
  270 
  271         /*
  272          * Indirect blocks first.
  273          */
  274         indir_lbn[SINGLE] = -NDADDR;
  275         indir_lbn[DOUBLE] = indir_lbn[SINGLE] - NINDIR(fs) - 1;
  276         indir_lbn[TRIPLE] = indir_lbn[DOUBLE] - NINDIR(fs) * NINDIR(fs) - 1;
  277         for (level = TRIPLE; level >= SINGLE; level--) {
  278                 bn = oip->i_ib[level];
  279                 if (bn != 0) {
  280                         error = ext2_indirtrunc(oip, indir_lbn[level],
  281                             fsbtodb(fs, bn), lastiblock[level], level, &count);
  282                         if (error)
  283                                 allerror = error;
  284                         blocksreleased += count;
  285                         if (lastiblock[level] < 0) {
  286                                 oip->i_ib[level] = 0;
  287                                 ext2_blkfree(oip, bn, fs->e2fs_fsize);
  288                                 blocksreleased += nblocks;
  289                         }
  290                 }
  291                 if (lastiblock[level] >= 0)
  292                         goto done;
  293         }
  294 
  295         /*
  296          * All whole direct blocks or frags.
  297          */
  298         for (i = NDADDR - 1; i > lastblock; i--) {
  299                 long bsize;
  300 
  301                 bn = oip->i_db[i];
  302                 if (bn == 0)
  303                         continue;
  304                 oip->i_db[i] = 0;
  305                 bsize = blksize(fs, oip, i);
  306                 ext2_blkfree(oip, bn, bsize);
  307                 blocksreleased += btodb(bsize);
  308         }
  309         if (lastblock < 0)
  310                 goto done;
  311 
  312         /*
  313          * Finally, look for a change in size of the
  314          * last direct block; release any frags.
  315          */
  316         bn = oip->i_db[lastblock];
  317         if (bn != 0) {
  318                 long oldspace, newspace;
  319 
  320                 /*
  321                  * Calculate amount of space we're giving
  322                  * back as old block size minus new block size.
  323                  */
  324                 oldspace = blksize(fs, oip, lastblock);
  325                 oip->i_size = length;
  326                 newspace = blksize(fs, oip, lastblock);
  327                 if (newspace == 0)
  328                         panic("ext2_truncate: newspace");
  329                 if (oldspace - newspace > 0) {
  330                         /*
  331                          * Block number of space to be free'd is
  332                          * the old block # plus the number of frags
  333                          * required for the storage we're keeping.
  334                          */
  335                         bn += numfrags(fs, newspace);
  336                         ext2_blkfree(oip, bn, oldspace - newspace);
  337                         blocksreleased += btodb(oldspace - newspace);
  338                 }
  339         }
  340 done:
  341 #ifdef INVARIANTS
  342         for (level = SINGLE; level <= TRIPLE; level++)
  343                 if (newblks[NDADDR + level] != oip->i_ib[level])
  344                         panic("itrunc1");
  345         for (i = 0; i < NDADDR; i++)
  346                 if (newblks[i] != oip->i_db[i])
  347                         panic("itrunc2");
  348         BO_LOCK(bo);
  349         if (length == 0 && (bo->bo_dirty.bv_cnt != 0 ||
  350             bo->bo_clean.bv_cnt != 0))
  351                 panic("itrunc3");
  352         BO_UNLOCK(bo);
  353 #endif  /* INVARIANTS */
  354         /*
  355          * Put back the real size.
  356          */
  357         oip->i_size = length;
  358         if (oip->i_blocks >= blocksreleased)
  359                 oip->i_blocks -= blocksreleased;
  360         else                            /* sanity */
  361                 oip->i_blocks = 0;
  362         oip->i_flag |= IN_CHANGE;
  363         vnode_pager_setsize(ovp, length);
  364         return (allerror);
  365 }
  366 
  367 /*
  368  * Release blocks associated with the inode ip and stored in the indirect
  369  * block bn.  Blocks are free'd in LIFO order up to (but not including)
  370  * lastbn.  If level is greater than SINGLE, the block is an indirect block
  371  * and recursive calls to indirtrunc must be used to cleanse other indirect
  372  * blocks.
  373  *
  374  * NB: triple indirect blocks are untested.
  375  */
  376 
  377 static int
  378 ext2_indirtrunc(struct inode *ip, daddr_t lbn, daddr_t dbn,
  379     daddr_t lastbn, int level, e4fs_daddr_t *countp)
  380 {
  381         struct buf *bp;
  382         struct m_ext2fs *fs = ip->i_e2fs;
  383         struct vnode *vp;
  384         e2fs_daddr_t *bap, *copy;
  385         int i, nblocks, error = 0, allerror = 0;
  386         e2fs_lbn_t nb, nlbn, last;
  387         e4fs_daddr_t blkcount, factor, blocksreleased = 0;
  388 
  389         /*
  390          * Calculate index in current block of last
  391          * block to be kept.  -1 indicates the entire
  392          * block so we need not calculate the index.
  393          */
  394         factor = 1;
  395         for (i = SINGLE; i < level; i++)
  396                 factor *= NINDIR(fs);
  397         last = lastbn;
  398         if (lastbn > 0)
  399                 last /= factor;
  400         nblocks = btodb(fs->e2fs_bsize);
  401         /*
  402          * Get buffer of block pointers, zero those entries corresponding
  403          * to blocks to be free'd, and update on disk copy first.  Since
  404          * double(triple) indirect before single(double) indirect, calls
  405          * to bmap on these blocks will fail.  However, we already have
  406          * the on disk address, so we have to set the b_blkno field
  407          * explicitly instead of letting bread do everything for us.
  408          */
  409         vp = ITOV(ip);
  410         bp = getblk(vp, lbn, (int)fs->e2fs_bsize, 0, 0, 0);
  411         if ((bp->b_flags & (B_DONE | B_DELWRI)) == 0) {
  412                 bp->b_iocmd = BIO_READ;
  413                 if (bp->b_bcount > bp->b_bufsize)
  414                         panic("ext2_indirtrunc: bad buffer size");
  415                 bp->b_blkno = dbn;
  416                 vfs_busy_pages(bp, 0);
  417                 bp->b_iooffset = dbtob(bp->b_blkno);
  418                 bstrategy(bp);
  419                 error = bufwait(bp);
  420         }
  421         if (error) {
  422                 brelse(bp);
  423                 *countp = 0;
  424                 return (error);
  425         }
  426         bap = (e2fs_daddr_t *)bp->b_data;
  427         copy = malloc(fs->e2fs_bsize, M_TEMP, M_WAITOK);
  428         bcopy((caddr_t)bap, (caddr_t)copy, (u_int)fs->e2fs_bsize);
  429         bzero((caddr_t)&bap[last + 1],
  430             (NINDIR(fs) - (last + 1)) * sizeof(e2fs_daddr_t));
  431         if (last == -1)
  432                 bp->b_flags |= B_INVAL;
  433         if (DOINGASYNC(vp)) {
  434                 bdwrite(bp);
  435         } else {
  436                 error = bwrite(bp);
  437                 if (error)
  438                         allerror = error;
  439         }
  440         bap = copy;
  441 
  442         /*
  443          * Recursively free totally unused blocks.
  444          */
  445         for (i = NINDIR(fs) - 1, nlbn = lbn + 1 - i * factor; i > last;
  446             i--, nlbn += factor) {
  447                 nb = bap[i];
  448                 if (nb == 0)
  449                         continue;
  450                 if (level > SINGLE) {
  451                         if ((error = ext2_indirtrunc(ip, nlbn,
  452                             fsbtodb(fs, nb), (int32_t)-1, level - 1, &blkcount)) != 0)
  453                                 allerror = error;
  454                         blocksreleased += blkcount;
  455                 }
  456                 ext2_blkfree(ip, nb, fs->e2fs_bsize);
  457                 blocksreleased += nblocks;
  458         }
  459 
  460         /*
  461          * Recursively free last partial block.
  462          */
  463         if (level > SINGLE && lastbn >= 0) {
  464                 last = lastbn % factor;
  465                 nb = bap[i];
  466                 if (nb != 0) {
  467                         if ((error = ext2_indirtrunc(ip, nlbn, fsbtodb(fs, nb),
  468                             last, level - 1, &blkcount)) != 0)
  469                                 allerror = error;
  470                         blocksreleased += blkcount;
  471                 }
  472         }
  473         free(copy, M_TEMP);
  474         *countp = blocksreleased;
  475         return (allerror);
  476 }
  477 
  478 /*
  479  *      discard preallocated blocks
  480  */
  481 int
  482 ext2_inactive(struct vop_inactive_args *ap)
  483 {
  484         struct vnode *vp = ap->a_vp;
  485         struct inode *ip = VTOI(vp);
  486         struct thread *td = ap->a_td;
  487         int mode, error = 0;
  488 
  489         /*
  490          * Ignore inodes related to stale file handles.
  491          */
  492         if (ip->i_mode == 0)
  493                 goto out;
  494         if (ip->i_nlink <= 0) {
  495                 ext2_extattr_free(ip);
  496                 error = ext2_truncate(vp, (off_t)0, 0, NOCRED, td);
  497                 ip->i_rdev = 0;
  498                 mode = ip->i_mode;
  499                 ip->i_mode = 0;
  500                 ip->i_flag |= IN_CHANGE | IN_UPDATE;
  501                 ext2_vfree(vp, ip->i_number, mode);
  502         }
  503         if (ip->i_flag & (IN_ACCESS | IN_CHANGE | IN_MODIFIED | IN_UPDATE))
  504                 ext2_update(vp, 0);
  505 out:
  506         /*
  507          * If we are done with the inode, reclaim it
  508          * so that it can be reused immediately.
  509          */
  510         if (ip->i_mode == 0)
  511                 vrecycle(vp);
  512         return (error);
  513 }
  514 
  515 /*
  516  * Reclaim an inode so that it can be used for other purposes.
  517  */
  518 int
  519 ext2_reclaim(struct vop_reclaim_args *ap)
  520 {
  521         struct inode *ip;
  522         struct vnode *vp = ap->a_vp;
  523 
  524         ip = VTOI(vp);
  525         if (ip->i_flag & IN_LAZYMOD) {
  526                 ip->i_flag |= IN_MODIFIED;
  527                 ext2_update(vp, 0);
  528         }
  529         vfs_hash_remove(vp);
  530         free(vp->v_data, M_EXT2NODE);
  531         vp->v_data = 0;
  532         vnode_destroy_vobject(vp);
  533         return (0);
  534 }

Cache object: f3c1a221bc0e53eaf1ddd4b3397efff0


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