The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/fs/ext2fs/ext2_lookup.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) 1989, 1993
    9  *      The Regents of the University of California.  All rights reserved.
   10  * (c) UNIX System Laboratories, Inc.
   11  * All or some portions of this file are derived from material licensed
   12  * to the University of California by American Telephone and Telegraph
   13  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
   14  * the permission of UNIX System Laboratories, Inc.
   15  *
   16  * Redistribution and use in source and binary forms, with or without
   17  * modification, are permitted provided that the following conditions
   18  * are met:
   19  * 1. Redistributions of source code must retain the above copyright
   20  *    notice, this list of conditions and the following disclaimer.
   21  * 2. Redistributions in binary form must reproduce the above copyright
   22  *    notice, this list of conditions and the following disclaimer in the
   23  *    documentation and/or other materials provided with the distribution.
   24  * 4. Neither the name of the University nor the names of its contributors
   25  *    may be used to endorse or promote products derived from this software
   26  *    without specific prior written permission.
   27  *
   28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   38  * SUCH DAMAGE.
   39  *
   40  *      @(#)ufs_lookup.c        8.6 (Berkeley) 4/1/94
   41  * $FreeBSD: releng/10.0/sys/fs/ext2fs/ext2_lookup.c 255338 2013-09-07 02:45:51Z pfg $
   42  */
   43 
   44 #include <sys/param.h>
   45 #include <sys/systm.h>
   46 #include <sys/namei.h>
   47 #include <sys/bio.h>
   48 #include <sys/buf.h>
   49 #include <sys/endian.h>
   50 #include <sys/mount.h>
   51 #include <sys/vnode.h>
   52 #include <sys/malloc.h>
   53 #include <sys/dirent.h>
   54 #include <sys/sysctl.h>
   55 
   56 #include <ufs/ufs/dir.h>
   57 
   58 #include <fs/ext2fs/inode.h>
   59 #include <fs/ext2fs/ext2_mount.h>
   60 #include <fs/ext2fs/ext2fs.h>
   61 #include <fs/ext2fs/ext2_dinode.h>
   62 #include <fs/ext2fs/ext2_dir.h>
   63 #include <fs/ext2fs/ext2_extern.h>
   64 
   65 #ifdef INVARIANTS
   66 static int dirchk = 1;
   67 #else
   68 static int dirchk = 0;
   69 #endif
   70 
   71 static SYSCTL_NODE(_vfs, OID_AUTO, e2fs, CTLFLAG_RD, 0, "EXT2FS filesystem");
   72 SYSCTL_INT(_vfs_e2fs, OID_AUTO, dircheck, CTLFLAG_RW, &dirchk, 0, "");
   73 
   74 /*
   75    DIRBLKSIZE in ffs is DEV_BSIZE (in most cases 512)
   76    while it is the native blocksize in ext2fs - thus, a #define
   77    is no longer appropriate
   78 */
   79 #undef  DIRBLKSIZ
   80 
   81 static u_char ext2_ft_to_dt[] = {
   82         DT_UNKNOWN,             /* EXT2_FT_UNKNOWN */
   83         DT_REG,                 /* EXT2_FT_REG_FILE */
   84         DT_DIR,                 /* EXT2_FT_DIR */
   85         DT_CHR,                 /* EXT2_FT_CHRDEV */
   86         DT_BLK,                 /* EXT2_FT_BLKDEV */
   87         DT_FIFO,                /* EXT2_FT_FIFO */
   88         DT_SOCK,                /* EXT2_FT_SOCK */
   89         DT_LNK,                 /* EXT2_FT_SYMLINK */
   90 };
   91 #define FTTODT(ft) \
   92     ((ft) < nitems(ext2_ft_to_dt) ? ext2_ft_to_dt[(ft)] : DT_UNKNOWN)
   93 
   94 static u_char dt_to_ext2_ft[] = {
   95         EXT2_FT_UNKNOWN,        /* DT_UNKNOWN */
   96         EXT2_FT_FIFO,           /* DT_FIFO */
   97         EXT2_FT_CHRDEV,         /* DT_CHR */
   98         EXT2_FT_UNKNOWN,        /* unused */
   99         EXT2_FT_DIR,            /* DT_DIR */
  100         EXT2_FT_UNKNOWN,        /* unused */
  101         EXT2_FT_BLKDEV,         /* DT_BLK */
  102         EXT2_FT_UNKNOWN,        /* unused */
  103         EXT2_FT_REG_FILE,       /* DT_REG */
  104         EXT2_FT_UNKNOWN,        /* unused */
  105         EXT2_FT_SYMLINK,        /* DT_LNK */
  106         EXT2_FT_UNKNOWN,        /* unused */
  107         EXT2_FT_SOCK,           /* DT_SOCK */
  108         EXT2_FT_UNKNOWN,        /* unused */
  109         EXT2_FT_UNKNOWN,        /* DT_WHT */
  110 };
  111 #define DTTOFT(dt) \
  112     ((dt) < nitems(dt_to_ext2_ft) ? dt_to_ext2_ft[(dt)] : EXT2_FT_UNKNOWN)
  113 
  114 static int      ext2_dirbadentry(struct vnode *dp, struct ext2fs_direct_2 *de,
  115                     int entryoffsetinblock);
  116 static int      ext2_is_dot_entry(struct componentname *cnp);
  117 static int      ext2_lookup_ino(struct vnode *vdp, struct vnode **vpp,
  118                     struct componentname *cnp, ino_t *dd_ino);
  119 
  120 static int
  121 ext2_is_dot_entry(struct componentname *cnp)
  122 {
  123         if (cnp->cn_namelen <= 2 && cnp->cn_nameptr[0] == '.' &&
  124             (cnp->cn_nameptr[1] == '.' || cnp->cn_nameptr[1] == ''))
  125                 return (1);
  126         return (0);
  127 }
  128 
  129 /*
  130  * Vnode op for reading directories.
  131  */
  132 int
  133 ext2_readdir(struct vop_readdir_args *ap)
  134 {
  135         struct vnode *vp = ap->a_vp;
  136         struct uio *uio = ap->a_uio;
  137         struct buf *bp;
  138         struct inode *ip;
  139         struct ext2fs_direct_2 *dp, *edp;
  140         u_long *cookies;
  141         struct dirent dstdp;
  142         off_t offset, startoffset;
  143         size_t readcnt, skipcnt;
  144         ssize_t startresid;
  145         int ncookies;
  146         int DIRBLKSIZ = VTOI(ap->a_vp)->i_e2fs->e2fs_bsize;
  147         int error;
  148 
  149         if (uio->uio_offset < 0)
  150                 return (EINVAL);
  151         ip = VTOI(vp);
  152         if (ap->a_ncookies != NULL) {
  153                 ncookies = uio->uio_resid;
  154                 if (uio->uio_offset >= ip->i_size)
  155                         ncookies = 0;
  156                 else if (ip->i_size - uio->uio_offset < ncookies)
  157                         ncookies = ip->i_size - uio->uio_offset;
  158                 ncookies = ncookies / (offsetof(struct ext2fs_direct_2,
  159                     e2d_namlen) + 4) + 1;
  160                 cookies = malloc(ncookies * sizeof(*cookies), M_TEMP, M_WAITOK);
  161                 *ap->a_ncookies = ncookies;
  162                 *ap->a_cookies = cookies;
  163         } else {
  164                 ncookies = 0;
  165                 cookies = NULL;
  166         }
  167         offset = startoffset = uio->uio_offset;
  168         startresid = uio->uio_resid;
  169         error = 0;
  170         while (error == 0 && uio->uio_resid > 0 &&
  171             uio->uio_offset < ip->i_size) {
  172                 error = ext2_blkatoff(vp, uio->uio_offset, NULL, &bp);
  173                 if (error)
  174                         break;
  175                 if (bp->b_offset + bp->b_bcount > ip->i_size)
  176                         readcnt = ip->i_size - bp->b_offset;
  177                 else
  178                         readcnt = bp->b_bcount;
  179                 skipcnt = (size_t)(uio->uio_offset - bp->b_offset) &
  180                     ~(size_t)(DIRBLKSIZ - 1);
  181                 offset = bp->b_offset + skipcnt;
  182                 dp = (struct ext2fs_direct_2 *)&bp->b_data[skipcnt];
  183                 edp = (struct ext2fs_direct_2 *)&bp->b_data[readcnt];
  184                 while (error == 0 && uio->uio_resid > 0 && dp < edp) {
  185                         if (dp->e2d_reclen <= offsetof(struct ext2fs_direct_2,
  186                             e2d_namlen) || (caddr_t)dp + dp->e2d_reclen >
  187                             (caddr_t)edp) {
  188                                 error = EIO;
  189                                 break;
  190                         }
  191                         /*-
  192                          * "New" ext2fs directory entries differ in 3 ways
  193                          * from ufs on-disk ones:
  194                          * - the name is not necessarily NUL-terminated.
  195                          * - the file type field always exists and always
  196                          *   follows the name length field.
  197                          * - the file type is encoded in a different way.
  198                          *
  199                          * "Old" ext2fs directory entries need no special
  200                          * conversions, since they are binary compatible
  201                          * with "new" entries having a file type of 0 (i.e.,
  202                          * EXT2_FT_UNKNOWN).  Splitting the old name length
  203                          * field didn't make a mess like it did in ufs,
  204                          * because ext2fs uses a machine-independent disk
  205                          * layout.
  206                          */
  207                         dstdp.d_namlen = dp->e2d_namlen;
  208                         dstdp.d_type = FTTODT(dp->e2d_type);
  209                         if (offsetof(struct ext2fs_direct_2, e2d_namlen) +
  210                             dstdp.d_namlen > dp->e2d_reclen) {
  211                                 error = EIO;
  212                                 break;
  213                         }
  214                         if (offset < startoffset || dp->e2d_ino == 0)
  215                                 goto nextentry;
  216                         dstdp.d_fileno = dp->e2d_ino;
  217                         dstdp.d_reclen = GENERIC_DIRSIZ(&dstdp);
  218                         bcopy(dp->e2d_name, dstdp.d_name, dstdp.d_namlen);
  219                         dstdp.d_name[dstdp.d_namlen] = '\0';
  220                         if (dstdp.d_reclen > uio->uio_resid) {
  221                                 if (uio->uio_resid == startresid)
  222                                         error = EINVAL;
  223                                 else
  224                                         error = EJUSTRETURN;
  225                                 break;
  226                         }
  227                         /* Advance dp. */
  228                         error = uiomove((caddr_t)&dstdp, dstdp.d_reclen, uio);
  229                         if (error)
  230                                 break;
  231                         if (cookies != NULL) {
  232                                 KASSERT(ncookies > 0,
  233                                     ("ext2_readdir: cookies buffer too small"));
  234                                 *cookies = offset + dp->e2d_reclen;
  235                                 cookies++;
  236                                 ncookies--;
  237                         }
  238 nextentry:
  239                         offset += dp->e2d_reclen;
  240                         dp = (struct ext2fs_direct_2 *)((caddr_t)dp +
  241                            dp->e2d_reclen);
  242                 }
  243                 bqrelse(bp);
  244                 uio->uio_offset = offset;
  245         }
  246         /* We need to correct uio_offset. */
  247         uio->uio_offset = offset;
  248         if (error == EJUSTRETURN)
  249                 error = 0;
  250         if (ap->a_ncookies != NULL) {
  251                 if (error == 0) {
  252                         ap->a_ncookies -= ncookies;
  253                 } else {
  254                         free(*ap->a_cookies, M_TEMP);
  255                         *ap->a_ncookies = 0;
  256                         *ap->a_cookies = NULL;
  257                 }
  258         }
  259         if (error == 0 && ap->a_eofflag)
  260                 *ap->a_eofflag = ip->i_size <= uio->uio_offset;
  261         return (error);
  262 }
  263 
  264 /*
  265  * Convert a component of a pathname into a pointer to a locked inode.
  266  * This is a very central and rather complicated routine.
  267  * If the file system is not maintained in a strict tree hierarchy,
  268  * this can result in a deadlock situation (see comments in code below).
  269  *
  270  * The cnp->cn_nameiop argument is LOOKUP, CREATE, RENAME, or DELETE depending
  271  * on whether the name is to be looked up, created, renamed, or deleted.
  272  * When CREATE, RENAME, or DELETE is specified, information usable in
  273  * creating, renaming, or deleting a directory entry may be calculated.
  274  * If flag has LOCKPARENT or'ed into it and the target of the pathname
  275  * exists, lookup returns both the target and its parent directory locked.
  276  * When creating or renaming and LOCKPARENT is specified, the target may
  277  * not be ".".  When deleting and LOCKPARENT is specified, the target may
  278  * be "."., but the caller must check to ensure it does an vrele and vput
  279  * instead of two vputs.
  280  *
  281  * Overall outline of ext2_lookup:
  282  *
  283  *      search for name in directory, to found or notfound
  284  * notfound:
  285  *      if creating, return locked directory, leaving info on available slots
  286  *      else return error
  287  * found:
  288  *      if at end of path and deleting, return information to allow delete
  289  *      if at end of path and rewriting (RENAME and LOCKPARENT), lock target
  290  *        inode and return info to allow rewrite
  291  *      if not at end, add name to cache; if at end and neither creating
  292  *        nor deleting, add name to cache
  293  */
  294 int
  295 ext2_lookup(struct vop_cachedlookup_args *ap)
  296 {
  297 
  298         return (ext2_lookup_ino(ap->a_dvp, ap->a_vpp, ap->a_cnp, NULL));
  299 }
  300 
  301 static int
  302 ext2_lookup_ino(struct vnode *vdp, struct vnode **vpp, struct componentname *cnp,
  303     ino_t *dd_ino)
  304 {
  305         struct inode *dp;               /* inode for directory being searched */
  306         struct buf *bp;                 /* a buffer of directory entries */
  307         struct ext2fs_direct_2 *ep;     /* the current directory entry */
  308         int entryoffsetinblock;         /* offset of ep in bp's buffer */
  309         struct ext2fs_searchslot ss;
  310         doff_t i_diroff;                /* cached i_diroff value */
  311         doff_t i_offset;                /* cached i_offset value */
  312         int numdirpasses;               /* strategy for directory search */
  313         doff_t endsearch;               /* offset to end directory search */
  314         doff_t prevoff;                 /* prev entry dp->i_offset */
  315         struct vnode *pdp;              /* saved dp during symlink work */
  316         struct vnode *tdp;              /* returned by VFS_VGET */
  317         doff_t enduseful;               /* pointer past last used dir slot */
  318         u_long bmask;                   /* block offset mask */
  319         int error;
  320         struct ucred *cred = cnp->cn_cred;
  321         int flags = cnp->cn_flags;
  322         int nameiop = cnp->cn_nameiop;
  323         ino_t ino, ino1;
  324         int ltype;
  325         int entry_found = 0;
  326 
  327         int     DIRBLKSIZ = VTOI(vdp)->i_e2fs->e2fs_bsize;
  328 
  329         if (vpp != NULL)
  330                 *vpp = NULL;
  331 
  332         dp = VTOI(vdp);
  333         bmask = VFSTOEXT2(vdp->v_mount)->um_mountp->mnt_stat.f_iosize - 1;
  334 restart:
  335         bp = NULL;
  336         ss.slotoffset = -1;
  337 
  338         /*
  339          * We now have a segment name to search for, and a directory to search.
  340          *
  341          * Suppress search for slots unless creating
  342          * file and at end of pathname, in which case
  343          * we watch for a place to put the new file in
  344          * case it doesn't already exist.
  345          */
  346         ino = 0;
  347         i_diroff = dp->i_diroff;
  348         ss.slotstatus = FOUND;
  349         ss.slotfreespace = ss.slotsize = ss.slotneeded = 0;
  350         if ((nameiop == CREATE || nameiop == RENAME) &&
  351             (flags & ISLASTCN)) {
  352                 ss.slotstatus = NONE;
  353                 ss.slotneeded = EXT2_DIR_REC_LEN(cnp->cn_namelen);
  354                 /* was
  355                 ss.slotneeded = (sizeof(struct direct) - MAXNAMLEN +
  356                         cnp->cn_namelen + 3) &~ 3; */
  357         }
  358 
  359         /*
  360          * Try to lookup dir entry using htree directory index.
  361          *
  362          * If we got an error or we want to find '.' or '..' entry,
  363          * we will fall back to linear search.
  364          */
  365         if (!ext2_is_dot_entry(cnp) && ext2_htree_has_idx(dp)) {
  366                 numdirpasses = 1;
  367                 entryoffsetinblock = 0;
  368                 switch (ext2_htree_lookup(dp, cnp->cn_nameptr, cnp->cn_namelen,
  369                                 &bp, &entryoffsetinblock, &i_offset, &prevoff,
  370                                 &enduseful, &ss)) {
  371                 case 0:
  372                         ep = (struct ext2fs_direct_2 *)((char *)bp->b_data +
  373                                 (i_offset & bmask));
  374                         goto foundentry;
  375                 case ENOENT:
  376                         i_offset = roundup2(dp->i_size, DIRBLKSIZ);
  377                         goto notfound;
  378                 default:
  379                         /*
  380                          * Something failed; just fallback to do a linear
  381                          * search.
  382                          */
  383                         break;
  384                 }
  385         }
  386 
  387         /*
  388          * If there is cached information on a previous search of
  389          * this directory, pick up where we last left off.
  390          * We cache only lookups as these are the most common
  391          * and have the greatest payoff. Caching CREATE has little
  392          * benefit as it usually must search the entire directory
  393          * to determine that the entry does not exist. Caching the
  394          * location of the last DELETE or RENAME has not reduced
  395          * profiling time and hence has been removed in the interest
  396          * of simplicity.
  397          */
  398         if (nameiop != LOOKUP || i_diroff == 0 ||
  399             i_diroff > dp->i_size) {
  400                 entryoffsetinblock = 0;
  401                 i_offset = 0;
  402                 numdirpasses = 1;
  403         } else {
  404                 i_offset = i_diroff;
  405                 if ((entryoffsetinblock = i_offset & bmask) &&
  406                     (error = ext2_blkatoff(vdp, (off_t)i_offset, NULL,
  407                     &bp)))
  408                         return (error);
  409                 numdirpasses = 2;
  410                 nchstats.ncs_2passes++;
  411         }
  412         prevoff = i_offset;
  413         endsearch = roundup2(dp->i_size, DIRBLKSIZ);
  414         enduseful = 0;
  415 
  416 searchloop:
  417         while (i_offset < endsearch) {
  418                 /*
  419                  * If necessary, get the next directory block.
  420                  */
  421                 if (bp != NULL)
  422                         brelse(bp);
  423                 error = ext2_blkatoff(vdp, (off_t)i_offset, NULL, &bp);
  424                 if (error != 0)
  425                         return (error);
  426                 entryoffsetinblock = 0;
  427                 /*
  428                  * If still looking for a slot, and at a DIRBLKSIZE
  429                  * boundary, have to start looking for free space again.
  430                  */
  431                 if (ss.slotstatus == NONE &&
  432                     (entryoffsetinblock & (DIRBLKSIZ - 1)) == 0) {
  433                         ss.slotoffset = -1;
  434                         ss.slotfreespace = 0;
  435                 }
  436                 error = ext2_search_dirblock(dp, bp->b_data, &entry_found,
  437                                 cnp->cn_nameptr, cnp->cn_namelen,
  438                                 &entryoffsetinblock, &i_offset, &prevoff,
  439                                 &enduseful, &ss);
  440                 if (error != 0) {
  441                         brelse(bp);
  442                         return (error);
  443                 }
  444                 if (entry_found) {
  445                         ep = (struct ext2fs_direct_2 *)((char *)bp->b_data +
  446                                 (entryoffsetinblock & bmask));
  447 foundentry:
  448                         ino = ep->e2d_ino;
  449                         goto found;
  450                 }
  451         }
  452 notfound:
  453         /*
  454          * If we started in the middle of the directory and failed
  455          * to find our target, we must check the beginning as well.
  456          */
  457         if (numdirpasses == 2) {
  458                 numdirpasses--;
  459                 i_offset = 0;
  460                 endsearch = i_diroff;
  461                 goto searchloop;
  462         }
  463         if (bp != NULL)
  464                 brelse(bp);
  465         /*
  466          * If creating, and at end of pathname and current
  467          * directory has not been removed, then can consider
  468          * allowing file to be created.
  469          */
  470         if ((nameiop == CREATE || nameiop == RENAME) &&
  471             (flags & ISLASTCN) && dp->i_nlink != 0) {
  472                 /*
  473                  * Access for write is interpreted as allowing
  474                  * creation of files in the directory.
  475                  */
  476                 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0)
  477                         return (error);
  478                 /*
  479                  * Return an indication of where the new directory
  480                  * entry should be put.  If we didn't find a slot,
  481                  * then set dp->i_count to 0 indicating
  482                  * that the new slot belongs at the end of the
  483                  * directory. If we found a slot, then the new entry
  484                  * can be put in the range from dp->i_offset to
  485                  * dp->i_offset + dp->i_count.
  486                  */
  487                 if (ss.slotstatus == NONE) {
  488                         dp->i_offset = roundup2(dp->i_size, DIRBLKSIZ);
  489                         dp->i_count = 0;
  490                         enduseful = dp->i_offset;
  491                 } else {
  492                         dp->i_offset = ss.slotoffset;
  493                         dp->i_count = ss.slotsize;
  494                         if (enduseful < ss.slotoffset + ss.slotsize)
  495                                 enduseful = ss.slotoffset + ss.slotsize;
  496                 }
  497                 dp->i_endoff = roundup2(enduseful, DIRBLKSIZ);
  498                 /*
  499                  * We return with the directory locked, so that
  500                  * the parameters we set up above will still be
  501                  * valid if we actually decide to do a direnter().
  502                  * We return ni_vp == NULL to indicate that the entry
  503                  * does not currently exist; we leave a pointer to
  504                  * the (locked) directory inode in ndp->ni_dvp.
  505                  * The pathname buffer is saved so that the name
  506                  * can be obtained later.
  507                  *
  508                  * NB - if the directory is unlocked, then this
  509                  * information cannot be used.
  510                  */
  511                 cnp->cn_flags |= SAVENAME;
  512                 return (EJUSTRETURN);
  513         }
  514         /*
  515          * Insert name into cache (as non-existent) if appropriate.
  516          */
  517         if ((cnp->cn_flags & MAKEENTRY) && nameiop != CREATE)
  518                 cache_enter(vdp, NULL, cnp);
  519         return (ENOENT);
  520 
  521 found:
  522         if (dd_ino != NULL)
  523                 *dd_ino = ino;
  524         if (numdirpasses == 2)
  525                 nchstats.ncs_pass2++;
  526         /*
  527          * Check that directory length properly reflects presence
  528          * of this entry.
  529          */
  530         if (entryoffsetinblock + EXT2_DIR_REC_LEN(ep->e2d_namlen)
  531                 > dp->i_size) {
  532                 ext2_dirbad(dp, i_offset, "i_size too small");
  533                 dp->i_size = entryoffsetinblock+EXT2_DIR_REC_LEN(ep->e2d_namlen);
  534                 dp->i_flag |= IN_CHANGE | IN_UPDATE;
  535         }
  536         brelse(bp);
  537 
  538         /*
  539          * Found component in pathname.
  540          * If the final component of path name, save information
  541          * in the cache as to where the entry was found.
  542          */
  543         if ((flags & ISLASTCN) && nameiop == LOOKUP)
  544                 dp->i_diroff = i_offset &~ (DIRBLKSIZ - 1);
  545         /*
  546          * If deleting, and at end of pathname, return
  547          * parameters which can be used to remove file.
  548          */
  549         if (nameiop == DELETE && (flags & ISLASTCN)) {
  550                 if (flags & LOCKPARENT)
  551                         ASSERT_VOP_ELOCKED(vdp, __FUNCTION__);
  552                 /*
  553                  * Write access to directory required to delete files.
  554                  */
  555                 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0)
  556                         return (error);
  557                 /*
  558                  * Return pointer to current entry in dp->i_offset,
  559                  * and distance past previous entry (if there
  560                  * is a previous entry in this block) in dp->i_count.
  561                  * Save directory inode pointer in ndp->ni_dvp for dirremove().
  562                  *
  563                  * Technically we shouldn't be setting these in the
  564                  * WANTPARENT case (first lookup in rename()), but any
  565                  * lookups that will result in directory changes will
  566                  * overwrite these.
  567                  */
  568                 dp->i_offset = i_offset;
  569                 if ((dp->i_offset & (DIRBLKSIZ - 1)) == 0)
  570                         dp->i_count = 0;
  571                 else
  572                         dp->i_count = dp->i_offset - prevoff;
  573                 if (dd_ino != NULL)
  574                         return (0);
  575                 if (dp->i_number == ino) {
  576                         VREF(vdp);
  577                         *vpp = vdp;
  578                         return (0);
  579                 }
  580                 if ((error = VFS_VGET(vdp->v_mount, ino, LK_EXCLUSIVE,
  581                     &tdp)) != 0)
  582                         return (error);
  583                 /*
  584                  * If directory is "sticky", then user must own
  585                  * the directory, or the file in it, else she
  586                  * may not delete it (unless she's root). This
  587                  * implements append-only directories.
  588                  */
  589                 if ((dp->i_mode & ISVTX) &&
  590                     cred->cr_uid != 0 &&
  591                     cred->cr_uid != dp->i_uid &&
  592                     VTOI(tdp)->i_uid != cred->cr_uid) {
  593                         vput(tdp);
  594                         return (EPERM);
  595                 }
  596                 *vpp = tdp;
  597                 return (0);
  598         }
  599 
  600         /*
  601          * If rewriting (RENAME), return the inode and the
  602          * information required to rewrite the present directory
  603          * Must get inode of directory entry to verify it's a
  604          * regular file, or empty directory.
  605          */
  606         if (nameiop == RENAME && (flags & ISLASTCN)) {
  607                 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0)
  608                         return (error);
  609                 /*
  610                  * Careful about locking second inode.
  611                  * This can only occur if the target is ".".
  612                  */
  613                 dp->i_offset = i_offset;
  614                 if (dp->i_number == ino)
  615                         return (EISDIR);
  616                 if (dd_ino != NULL)
  617                         return (0);
  618                 if ((error = VFS_VGET(vdp->v_mount, ino, LK_EXCLUSIVE,
  619                     &tdp)) != 0)
  620                         return (error);
  621                 *vpp = tdp;
  622                 cnp->cn_flags |= SAVENAME;
  623                 return (0);
  624         }
  625         if (dd_ino != NULL)
  626                 return (0);
  627 
  628         /*
  629          * Step through the translation in the name.  We do not `vput' the
  630          * directory because we may need it again if a symbolic link
  631          * is relative to the current directory.  Instead we save it
  632          * unlocked as "pdp".  We must get the target inode before unlocking
  633          * the directory to insure that the inode will not be removed
  634          * before we get it.  We prevent deadlock by always fetching
  635          * inodes from the root, moving down the directory tree. Thus
  636          * when following backward pointers ".." we must unlock the
  637          * parent directory before getting the requested directory.
  638          * There is a potential race condition here if both the current
  639          * and parent directories are removed before the VFS_VGET for the
  640          * inode associated with ".." returns.  We hope that this occurs
  641          * infrequently since we cannot avoid this race condition without
  642          * implementing a sophisticated deadlock detection algorithm.
  643          * Note also that this simple deadlock detection scheme will not
  644          * work if the file system has any hard links other than ".."
  645          * that point backwards in the directory structure.
  646          */
  647         pdp = vdp;
  648         if (flags & ISDOTDOT) {
  649                 error = vn_vget_ino(pdp, ino, cnp->cn_lkflags, &tdp);
  650                 if (pdp->v_iflag & VI_DOOMED) {
  651                         if (error == 0)
  652                                 vput(tdp);
  653                         error = ENOENT;
  654                 }
  655                 if (error)
  656                         return (error);
  657                 /*
  658                  * Recheck that ".." entry in the vdp directory points
  659                  * to the inode we looked up before vdp lock was
  660                  * dropped.
  661                  */
  662                 error = ext2_lookup_ino(pdp, NULL, cnp, &ino1);
  663                 if (error) {
  664                         vput(tdp);
  665                         return (error);
  666                 }
  667                 if (ino1 != ino) {
  668                         vput(tdp);
  669                         goto restart;
  670                 }
  671                 *vpp = tdp;
  672         } else if (dp->i_number == ino) {
  673                 VREF(vdp);      /* we want ourself, ie "." */
  674                 /*
  675                  * When we lookup "." we still can be asked to lock it
  676                  * differently.
  677                  */
  678                 ltype = cnp->cn_lkflags & LK_TYPE_MASK;
  679                 if (ltype != VOP_ISLOCKED(vdp)) {
  680                         if (ltype == LK_EXCLUSIVE)
  681                                 vn_lock(vdp, LK_UPGRADE | LK_RETRY);
  682                         else /* if (ltype == LK_SHARED) */
  683                                 vn_lock(vdp, LK_DOWNGRADE | LK_RETRY);
  684                 }
  685                 *vpp = vdp;
  686         } else {
  687                 if ((error = VFS_VGET(vdp->v_mount, ino, cnp->cn_lkflags,
  688                     &tdp)) != 0)
  689                         return (error);
  690                 *vpp = tdp;
  691         }
  692 
  693         /*
  694          * Insert name into cache if appropriate.
  695          */
  696         if (cnp->cn_flags & MAKEENTRY)
  697                 cache_enter(vdp, *vpp, cnp);
  698         return (0);
  699 }
  700 
  701 int
  702 ext2_search_dirblock(struct inode *ip, void *data, int *foundp,
  703         const char *name, int namelen, int *entryoffsetinblockp,
  704         doff_t *offp, doff_t *prevoffp, doff_t *endusefulp,
  705         struct ext2fs_searchslot *ssp)
  706 {
  707         struct vnode *vdp;
  708         struct ext2fs_direct_2 *ep, *top;
  709         uint32_t bsize = ip->i_e2fs->e2fs_bsize;
  710         int offset = *entryoffsetinblockp;
  711         int namlen;
  712 
  713         vdp = ITOV(ip);
  714 
  715         ep = (struct ext2fs_direct_2 *)((char *)data + offset);
  716         top = (struct ext2fs_direct_2 *)((char *)data +
  717                 bsize - EXT2_DIR_REC_LEN(0));
  718 
  719         while (ep < top) {
  720                 /*
  721                  * Full validation checks are slow, so we only check
  722                  * enough to insure forward progress through the
  723                  * directory. Complete checks can be run by setting
  724                  * "vfs.e2fs.dirchk" to be true.
  725                  */
  726                 if (ep->e2d_reclen == 0 ||
  727                     (dirchk && ext2_dirbadentry(vdp, ep, offset))) {
  728                         int i;
  729                         ext2_dirbad(ip, *offp, "mangled entry");
  730                         i = bsize - (offset & (bsize - 1));
  731                         *offp += i;
  732                         offset += i;
  733                         continue;
  734                 }
  735 
  736                 /*
  737                  * If an appropriate sized slot has not yet been found,
  738                  * check to see if one is available. Also accumulate space
  739                  * in the current block so that we can determine if
  740                  * compaction is viable.
  741                  */
  742                 if (ssp->slotstatus != FOUND) {
  743                         int size = ep->e2d_reclen;
  744 
  745                         if (ep->e2d_ino != 0)
  746                                 size -= EXT2_DIR_REC_LEN(ep->e2d_namlen);
  747                         if (size > 0) {
  748                                 if (size >= ssp->slotneeded) {
  749                                         ssp->slotstatus = FOUND;
  750                                         ssp->slotoffset = *offp;
  751                                         ssp->slotsize = ep->e2d_reclen;
  752                                 } else if (ssp->slotstatus == NONE) {
  753                                         ssp->slotfreespace += size;
  754                                         if (ssp->slotoffset == -1)
  755                                                 ssp->slotoffset = *offp;
  756                                         if (ssp->slotfreespace >= ssp->slotneeded) {
  757                                                 ssp->slotstatus = COMPACT;
  758                                                 ssp->slotsize = *offp +
  759                                                         ep->e2d_reclen -
  760                                                         ssp->slotoffset;
  761                                         }
  762                                 }
  763                         }
  764                 }
  765 
  766                 /*
  767                  * Check for a name match.
  768                  */
  769                 if (ep->e2d_ino) {
  770                         namlen = ep->e2d_namlen;
  771                         if (namlen == namelen &&
  772                             !bcmp(name, ep->e2d_name, (unsigned)namlen)) {
  773                                 /*
  774                                  * Save directory entry's inode number and
  775                                  * reclen in ndp->ni_ufs area, and release
  776                                  * directory buffer.
  777                                  */
  778                                 *foundp = 1;
  779                                 return (0);
  780                         }
  781                 }
  782                 *prevoffp = *offp;
  783                 *offp += ep->e2d_reclen;
  784                 offset += ep->e2d_reclen;
  785                 *entryoffsetinblockp = offset;
  786                 if (ep->e2d_ino)
  787                         *endusefulp = *offp;
  788                 /*
  789                  * Get pointer to the next entry.
  790                  */
  791                 ep = (struct ext2fs_direct_2 *)((char *)data + offset);
  792         }
  793 
  794         return (0);
  795 }
  796 
  797 void
  798 ext2_dirbad(struct inode *ip, doff_t offset, char *how)
  799 {
  800         struct mount *mp;
  801 
  802         mp = ITOV(ip)->v_mount;
  803         if ((mp->mnt_flag & MNT_RDONLY) == 0)
  804                 panic("ext2_dirbad: %s: bad dir ino %lu at offset %ld: %s\n",
  805                         mp->mnt_stat.f_mntonname, (u_long)ip->i_number,(long)offset, how);
  806         else
  807         (void)printf("%s: bad dir ino %lu at offset %ld: %s\n",
  808             mp->mnt_stat.f_mntonname, (u_long)ip->i_number, (long)offset, how);
  809 
  810 }
  811 
  812 /*
  813  * Do consistency checking on a directory entry:
  814  *      record length must be multiple of 4
  815  *      entry must fit in rest of its DIRBLKSIZ block
  816  *      record must be large enough to contain entry
  817  *      name is not longer than MAXNAMLEN
  818  *      name must be as long as advertised, and null terminated
  819  */
  820 /*
  821  *      changed so that it confirms to ext2_check_dir_entry
  822  */
  823 static int
  824 ext2_dirbadentry(struct vnode *dp, struct ext2fs_direct_2 *de,
  825     int entryoffsetinblock)
  826 {
  827         int     DIRBLKSIZ = VTOI(dp)->i_e2fs->e2fs_bsize;
  828 
  829         char * error_msg = NULL;
  830 
  831         if (de->e2d_reclen < EXT2_DIR_REC_LEN(1))
  832                 error_msg = "rec_len is smaller than minimal";
  833         else if (de->e2d_reclen % 4 != 0)
  834                 error_msg = "rec_len % 4 != 0";
  835         else if (de->e2d_reclen < EXT2_DIR_REC_LEN(de->e2d_namlen))
  836                 error_msg = "reclen is too small for name_len";
  837         else if (entryoffsetinblock + de->e2d_reclen > DIRBLKSIZ)
  838                 error_msg = "directory entry across blocks";
  839         /* else LATER
  840              if (de->inode > dir->i_sb->u.ext2_sb.s_es->s_inodes_count)
  841                 error_msg = "inode out of bounds";
  842         */
  843 
  844         if (error_msg != NULL) {
  845                 printf("bad directory entry: %s\n", error_msg);
  846                 printf("offset=%d, inode=%lu, rec_len=%u, name_len=%u\n",
  847                         entryoffsetinblock, (unsigned long)de->e2d_ino,
  848                         de->e2d_reclen, de->e2d_namlen);
  849         }
  850         return error_msg == NULL ? 0 : 1;
  851 }
  852 
  853 /*
  854  * Write a directory entry after a call to namei, using the parameters
  855  * that it left in nameidata.  The argument ip is the inode which the new
  856  * directory entry will refer to.  Dvp is a pointer to the directory to
  857  * be written, which was left locked by namei. Remaining parameters
  858  * (dp->i_offset, dp->i_count) indicate how the space for the new
  859  * entry is to be obtained.
  860  */
  861 int
  862 ext2_direnter(struct inode *ip, struct vnode *dvp, struct componentname *cnp)
  863 {
  864         struct inode *dp;
  865         struct ext2fs_direct_2 newdir;
  866         struct iovec aiov;
  867         struct uio auio;
  868         int error, newentrysize;
  869         int DIRBLKSIZ = ip->i_e2fs->e2fs_bsize;
  870 
  871 
  872 #ifdef INVARIANTS
  873         if ((cnp->cn_flags & SAVENAME) == 0)
  874                 panic("ext2_direnter: missing name");
  875 #endif
  876         dp = VTOI(dvp);
  877         newdir.e2d_ino = ip->i_number;
  878         newdir.e2d_namlen = cnp->cn_namelen;
  879         if (EXT2_HAS_INCOMPAT_FEATURE(ip->i_e2fs,
  880             EXT2F_INCOMPAT_FTYPE))
  881                 newdir.e2d_type = DTTOFT(IFTODT(ip->i_mode));
  882         else
  883                 newdir.e2d_type = EXT2_FT_UNKNOWN;
  884         bcopy(cnp->cn_nameptr, newdir.e2d_name, (unsigned)cnp->cn_namelen + 1);
  885         newentrysize = EXT2_DIR_REC_LEN(newdir.e2d_namlen);
  886 
  887 #ifdef EXT2FS_HTREE
  888         if (ext2_htree_has_idx(dp)) {
  889                 error = ext2_htree_add_entry(dvp, &newdir, cnp);
  890                 if (error) {
  891                         dp->i_flags &= ~EXT4_INDEX;
  892                         dp->i_flags |= IN_CHANGE | IN_UPDATE;
  893                 }
  894                 return (error);
  895         }
  896 
  897         if (EXT2_HAS_COMPAT_FEATURE(ip->i_e2fs, EXT2F_COMPAT_DIRHASHINDEX) &&
  898             !ext2_htree_has_idx(dp)) {
  899                 if ((dp->i_size / DIRBLKSIZ) == 1 &&
  900                     dp->i_offset == DIRBLKSIZ) {
  901                         /*
  902                          * Making indexed directory when one block is not
  903                          * enough to save all entries.
  904                          */
  905                         return ext2_htree_create_index(dvp, cnp, &newdir);
  906                 }
  907         }
  908 #endif  /* EXT2FS_HTREE */
  909 
  910         if (dp->i_count == 0) {
  911                 /*
  912                  * If dp->i_count is 0, then namei could find no
  913                  * space in the directory. Here, dp->i_offset will
  914                  * be on a directory block boundary and we will write the
  915                  * new entry into a fresh block.
  916                  */
  917                 if (dp->i_offset & (DIRBLKSIZ - 1))
  918                         panic("ext2_direnter: newblk");
  919                 auio.uio_offset = dp->i_offset;
  920                 newdir.e2d_reclen = DIRBLKSIZ;
  921                 auio.uio_resid = newentrysize;
  922                 aiov.iov_len = newentrysize;
  923                 aiov.iov_base = (caddr_t)&newdir;
  924                 auio.uio_iov = &aiov;
  925                 auio.uio_iovcnt = 1;
  926                 auio.uio_rw = UIO_WRITE;
  927                 auio.uio_segflg = UIO_SYSSPACE;
  928                 auio.uio_td = (struct thread *)0;
  929                 error = VOP_WRITE(dvp, &auio, IO_SYNC, cnp->cn_cred);
  930                 if (DIRBLKSIZ >
  931                     VFSTOEXT2(dvp->v_mount)->um_mountp->mnt_stat.f_bsize)
  932                         /* XXX should grow with balloc() */
  933                         panic("ext2_direnter: frag size");
  934                 else if (!error) {
  935                         dp->i_size = roundup2(dp->i_size, DIRBLKSIZ);
  936                         dp->i_flag |= IN_CHANGE;
  937                 }
  938                 return (error);
  939         }
  940 
  941         error = ext2_add_entry(dvp, &newdir);
  942         if (!error && dp->i_endoff && dp->i_endoff < dp->i_size)
  943                 error = ext2_truncate(dvp, (off_t)dp->i_endoff, IO_SYNC,
  944                     cnp->cn_cred, cnp->cn_thread);
  945         return (error);
  946 }
  947 
  948 /*
  949  * Insert an entry into the directory block.
  950  * Compact the contents.
  951  */
  952 int
  953 ext2_add_entry(struct vnode *dvp, struct ext2fs_direct_2 *entry)
  954 {
  955         struct ext2fs_direct_2 *ep, *nep;
  956         struct inode *dp;
  957         struct buf *bp;
  958         u_int dsize;
  959         int error, loc, newentrysize, spacefree;
  960         char *dirbuf;
  961 
  962         dp = VTOI(dvp);
  963 
  964         /*
  965          * If dp->i_count is non-zero, then namei found space
  966          * for the new entry in the range dp->i_offset to
  967          * dp->i_offset + dp->i_count in the directory.
  968          * To use this space, we may have to compact the entries located
  969          * there, by copying them together towards the beginning of the
  970          * block, leaving the free space in one usable chunk at the end.
  971          */
  972 
  973         /*
  974          * Increase size of directory if entry eats into new space.
  975          * This should never push the size past a new multiple of
  976          * DIRBLKSIZE.
  977          *
  978          * N.B. - THIS IS AN ARTIFACT OF 4.2 AND SHOULD NEVER HAPPEN.
  979          */
  980         if (dp->i_offset + dp->i_count > dp->i_size)
  981                 dp->i_size = dp->i_offset + dp->i_count;
  982         /*
  983          * Get the block containing the space for the new directory entry.
  984          */
  985         if ((error = ext2_blkatoff(dvp, (off_t)dp->i_offset, &dirbuf,
  986             &bp)) != 0)
  987                 return (error);
  988         /*
  989          * Find space for the new entry. In the simple case, the entry at
  990          * offset base will have the space. If it does not, then namei
  991          * arranged that compacting the region dp->i_offset to
  992          * dp->i_offset + dp->i_count would yield the
  993          * space.
  994          */
  995         newentrysize = EXT2_DIR_REC_LEN(entry->e2d_namlen);
  996         ep = (struct ext2fs_direct_2 *)dirbuf;
  997         dsize = EXT2_DIR_REC_LEN(ep->e2d_namlen);
  998         spacefree = ep->e2d_reclen - dsize;
  999         for (loc = ep->e2d_reclen; loc < dp->i_count; ) {
 1000                 nep = (struct ext2fs_direct_2 *)(dirbuf + loc);
 1001                 if (ep->e2d_ino) {
 1002                         /* trim the existing slot */
 1003                         ep->e2d_reclen = dsize;
 1004                         ep = (struct ext2fs_direct_2 *)((char *)ep + dsize);
 1005                 } else {
 1006                         /* overwrite; nothing there; header is ours */
 1007                         spacefree += dsize;
 1008                 }
 1009                 dsize = EXT2_DIR_REC_LEN(nep->e2d_namlen);
 1010                 spacefree += nep->e2d_reclen - dsize;
 1011                 loc += nep->e2d_reclen;
 1012                 bcopy((caddr_t)nep, (caddr_t)ep, dsize);
 1013         }
 1014         /*
 1015          * Update the pointer fields in the previous entry (if any),
 1016          * copy in the new entry, and write out the block.
 1017          */
 1018         if (ep->e2d_ino == 0) {
 1019                 if (spacefree + dsize < newentrysize)
 1020                         panic("ext2_direnter: compact1");
 1021                 entry->e2d_reclen = spacefree + dsize;
 1022         } else {
 1023                 if (spacefree < newentrysize)
 1024                         panic("ext2_direnter: compact2");
 1025                 entry->e2d_reclen = spacefree;
 1026                 ep->e2d_reclen = dsize;
 1027                 ep = (struct ext2fs_direct_2 *)((char *)ep + dsize);
 1028         }
 1029         bcopy((caddr_t)entry, (caddr_t)ep, (u_int)newentrysize);
 1030         if (DOINGASYNC(dvp)) {
 1031                 bdwrite(bp);
 1032                 error = 0;
 1033         } else {
 1034                 error = bwrite(bp);
 1035         }
 1036         dp->i_flag |= IN_CHANGE | IN_UPDATE;
 1037         return (error);
 1038 }
 1039 
 1040 /*
 1041  * Remove a directory entry after a call to namei, using
 1042  * the parameters which it left in nameidata. The entry
 1043  * dp->i_offset contains the offset into the directory of the
 1044  * entry to be eliminated.  The dp->i_count field contains the
 1045  * size of the previous record in the directory.  If this
 1046  * is 0, the first entry is being deleted, so we need only
 1047  * zero the inode number to mark the entry as free.  If the
 1048  * entry is not the first in the directory, we must reclaim
 1049  * the space of the now empty record by adding the record size
 1050  * to the size of the previous entry.
 1051  */
 1052 int
 1053 ext2_dirremove(struct vnode *dvp, struct componentname *cnp)
 1054 {
 1055         struct inode *dp;
 1056         struct ext2fs_direct_2 *ep, *rep;
 1057         struct buf *bp;
 1058         int error;
 1059 
 1060         dp = VTOI(dvp);
 1061         if (dp->i_count == 0) {
 1062                 /*
 1063                  * First entry in block: set d_ino to zero.
 1064                  */
 1065                 if ((error =
 1066                     ext2_blkatoff(dvp, (off_t)dp->i_offset, (char **)&ep,
 1067                     &bp)) != 0)
 1068                         return (error);
 1069                 ep->e2d_ino = 0;
 1070                 error = bwrite(bp);
 1071                 dp->i_flag |= IN_CHANGE | IN_UPDATE;
 1072                 return (error);
 1073         }
 1074         /*
 1075          * Collapse new free space into previous entry.
 1076          */
 1077         if ((error = ext2_blkatoff(dvp, (off_t)(dp->i_offset - dp->i_count),
 1078             (char **)&ep, &bp)) != 0)
 1079                 return (error);
 1080 
 1081         /* Set 'rep' to the entry being removed. */
 1082         if (dp->i_count == 0)
 1083                 rep = ep;
 1084         else
 1085                 rep = (struct ext2fs_direct_2 *)((char *)ep + ep->e2d_reclen);
 1086         ep->e2d_reclen += rep->e2d_reclen;
 1087         if (DOINGASYNC(dvp) && dp->i_count != 0)
 1088                 bdwrite(bp);
 1089         else
 1090                 error = bwrite(bp);
 1091         dp->i_flag |= IN_CHANGE | IN_UPDATE;
 1092         return (error);
 1093 }
 1094 
 1095 /*
 1096  * Rewrite an existing directory entry to point at the inode
 1097  * supplied.  The parameters describing the directory entry are
 1098  * set up by a call to namei.
 1099  */
 1100 int
 1101 ext2_dirrewrite(struct inode *dp, struct inode *ip, struct componentname *cnp)
 1102 {
 1103         struct buf *bp;
 1104         struct ext2fs_direct_2 *ep;
 1105         struct vnode *vdp = ITOV(dp);
 1106         int error;
 1107 
 1108         if ((error = ext2_blkatoff(vdp, (off_t)dp->i_offset, (char **)&ep,
 1109             &bp)) != 0)
 1110                 return (error);
 1111         ep->e2d_ino = ip->i_number;
 1112         if (EXT2_HAS_INCOMPAT_FEATURE(ip->i_e2fs,
 1113             EXT2F_INCOMPAT_FTYPE))
 1114                 ep->e2d_type = DTTOFT(IFTODT(ip->i_mode));
 1115         else
 1116                 ep->e2d_type = EXT2_FT_UNKNOWN;
 1117         error = bwrite(bp);
 1118         dp->i_flag |= IN_CHANGE | IN_UPDATE;
 1119         return (error);
 1120 }
 1121 
 1122 /*
 1123  * Check if a directory is empty or not.
 1124  * Inode supplied must be locked.
 1125  *
 1126  * Using a struct dirtemplate here is not precisely
 1127  * what we want, but better than using a struct direct.
 1128  *
 1129  * NB: does not handle corrupted directories.
 1130  */
 1131 int
 1132 ext2_dirempty(struct inode *ip, ino_t parentino, struct ucred *cred)
 1133 {
 1134         off_t off;
 1135         struct dirtemplate dbuf;
 1136         struct ext2fs_direct_2 *dp = (struct ext2fs_direct_2 *)&dbuf;
 1137         int error, namlen;
 1138         ssize_t count;
 1139 #define MINDIRSIZ (sizeof(struct dirtemplate) / 2)
 1140 
 1141         for (off = 0; off < ip->i_size; off += dp->e2d_reclen) {
 1142                 error = vn_rdwr(UIO_READ, ITOV(ip), (caddr_t)dp, MINDIRSIZ,
 1143                     off, UIO_SYSSPACE, IO_NODELOCKED | IO_NOMACCHECK, cred,
 1144                     NOCRED, &count, (struct thread *)0);
 1145                 /*
 1146                  * Since we read MINDIRSIZ, residual must
 1147                  * be 0 unless we're at end of file.
 1148                  */
 1149                 if (error || count != 0)
 1150                         return (0);
 1151                 /* avoid infinite loops */
 1152                 if (dp->e2d_reclen == 0)
 1153                         return (0);
 1154                 /* skip empty entries */
 1155                 if (dp->e2d_ino == 0)
 1156                         continue;
 1157                 /* accept only "." and ".." */
 1158                 namlen = dp->e2d_namlen;
 1159                 if (namlen > 2)
 1160                         return (0);
 1161                 if (dp->e2d_name[0] != '.')
 1162                         return (0);
 1163                 /*
 1164                  * At this point namlen must be 1 or 2.
 1165                  * 1 implies ".", 2 implies ".." if second
 1166                  * char is also "."
 1167                  */
 1168                 if (namlen == 1)
 1169                         continue;
 1170                 if (dp->e2d_name[1] == '.' && dp->e2d_ino == parentino)
 1171                         continue;
 1172                 return (0);
 1173         }
 1174         return (1);
 1175 }
 1176 
 1177 /*
 1178  * Check if source directory is in the path of the target directory.
 1179  * Target is supplied locked, source is unlocked.
 1180  * The target is always vput before returning.
 1181  */
 1182 int
 1183 ext2_checkpath(struct inode *source, struct inode *target, struct ucred *cred)
 1184 {
 1185         struct vnode *vp;
 1186         int error, namlen;
 1187         struct dirtemplate dirbuf;
 1188 
 1189         vp = ITOV(target);
 1190         if (target->i_number == source->i_number) {
 1191                 error = EEXIST;
 1192                 goto out;
 1193         }
 1194         if (target->i_number == EXT2_ROOTINO) {
 1195                 error = 0;
 1196                 goto out;
 1197         }
 1198 
 1199         for (;;) {
 1200                 if (vp->v_type != VDIR) {
 1201                         error = ENOTDIR;
 1202                         break;
 1203                 }
 1204                 error = vn_rdwr(UIO_READ, vp, (caddr_t)&dirbuf,
 1205                         sizeof(struct dirtemplate), (off_t)0, UIO_SYSSPACE,
 1206                         IO_NODELOCKED | IO_NOMACCHECK, cred, NOCRED, NULL,
 1207                         NULL);
 1208                 if (error != 0)
 1209                         break;
 1210                 namlen = dirbuf.dotdot_type;    /* like ufs little-endian */
 1211                 if (namlen != 2 ||
 1212                     dirbuf.dotdot_name[0] != '.' ||
 1213                     dirbuf.dotdot_name[1] != '.') {
 1214                         error = ENOTDIR;
 1215                         break;
 1216                 }
 1217                 if (dirbuf.dotdot_ino == source->i_number) {
 1218                         error = EINVAL;
 1219                         break;
 1220                 }
 1221                 if (dirbuf.dotdot_ino == EXT2_ROOTINO)
 1222                         break;
 1223                 vput(vp);
 1224                 if ((error = VFS_VGET(vp->v_mount, dirbuf.dotdot_ino,
 1225                     LK_EXCLUSIVE, &vp)) != 0) {
 1226                         vp = NULL;
 1227                         break;
 1228                 }
 1229         }
 1230 
 1231 out:
 1232         if (error == ENOTDIR)
 1233                 printf("checkpath: .. not a directory\n");
 1234         if (vp != NULL)
 1235                 vput(vp);
 1236         return (error);
 1237 }

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