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  * SPDX-License-Identifier: BSD-3-Clause
    9  *
   10  * Copyright (c) 1989, 1993
   11  *      The Regents of the University of California.  All rights reserved.
   12  * (c) UNIX System Laboratories, Inc.
   13  * All or some portions of this file are derived from material licensed
   14  * to the University of California by American Telephone and Telegraph
   15  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
   16  * the permission of UNIX System Laboratories, Inc.
   17  *
   18  * Redistribution and use in source and binary forms, with or without
   19  * modification, are permitted provided that the following conditions
   20  * are met:
   21  * 1. Redistributions of source code must retain the above copyright
   22  *    notice, this list of conditions and the following disclaimer.
   23  * 2. Redistributions in binary form must reproduce the above copyright
   24  *    notice, this list of conditions and the following disclaimer in the
   25  *    documentation and/or other materials provided with the distribution.
   26  * 3. Neither the name of the University nor the names of its contributors
   27  *    may be used to endorse or promote products derived from this software
   28  *    without specific prior written permission.
   29  *
   30  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   31  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   32  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   33  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   34  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   35  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   36  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   37  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   38  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   39  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   40  * SUCH DAMAGE.
   41  *
   42  *      @(#)ufs_lookup.c        8.6 (Berkeley) 4/1/94
   43  * $FreeBSD$
   44  */
   45 
   46 #include <sys/param.h>
   47 #include <sys/systm.h>
   48 #include <sys/namei.h>
   49 #include <sys/bio.h>
   50 #include <sys/buf.h>
   51 #include <sys/endian.h>
   52 #include <sys/mount.h>
   53 #include <sys/vnode.h>
   54 #include <sys/malloc.h>
   55 #include <sys/dirent.h>
   56 #include <sys/sdt.h>
   57 #include <sys/sysctl.h>
   58 
   59 #include <ufs/ufs/dir.h>
   60 
   61 #include <fs/ext2fs/fs.h>
   62 #include <fs/ext2fs/inode.h>
   63 #include <fs/ext2fs/ext2_mount.h>
   64 #include <fs/ext2fs/ext2fs.h>
   65 #include <fs/ext2fs/ext2_dinode.h>
   66 #include <fs/ext2fs/ext2_dir.h>
   67 #include <fs/ext2fs/ext2_extern.h>
   68 #include <fs/ext2fs/fs.h>
   69 
   70 SDT_PROVIDER_DECLARE(ext2fs);
   71 /*
   72  * ext2fs trace probe:
   73  * arg0: verbosity. Higher numbers give more verbose messages
   74  * arg1: Textual message
   75  */
   76 SDT_PROBE_DEFINE2(ext2fs, , lookup, trace, "int", "char*");
   77 SDT_PROBE_DEFINE4(ext2fs, , trace, ext2_dirbad_error,
   78     "char*", "ino_t", "doff_t", "char*");
   79 SDT_PROBE_DEFINE5(ext2fs, , trace, ext2_dirbadentry_error,
   80     "char*", "int", "uint32_t", "uint16_t", "uint8_t");
   81 
   82 static SYSCTL_NODE(_vfs, OID_AUTO, e2fs, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
   83     "EXT2FS filesystem");
   84 
   85 /*
   86    DIRBLKSIZE in ffs is DEV_BSIZE (in most cases 512)
   87    while it is the native blocksize in ext2fs - thus, a #define
   88    is no longer appropriate
   89 */
   90 #undef  DIRBLKSIZ
   91 
   92 static u_char ext2_ft_to_dt[] = {
   93         DT_UNKNOWN,             /* EXT2_FT_UNKNOWN */
   94         DT_REG,                 /* EXT2_FT_REG_FILE */
   95         DT_DIR,                 /* EXT2_FT_DIR */
   96         DT_CHR,                 /* EXT2_FT_CHRDEV */
   97         DT_BLK,                 /* EXT2_FT_BLKDEV */
   98         DT_FIFO,                /* EXT2_FT_FIFO */
   99         DT_SOCK,                /* EXT2_FT_SOCK */
  100         DT_LNK,                 /* EXT2_FT_SYMLINK */
  101 };
  102 #define FTTODT(ft) \
  103     ((ft) < nitems(ext2_ft_to_dt) ? ext2_ft_to_dt[(ft)] : DT_UNKNOWN)
  104 
  105 static u_char dt_to_ext2_ft[] = {
  106         EXT2_FT_UNKNOWN,        /* DT_UNKNOWN */
  107         EXT2_FT_FIFO,           /* DT_FIFO */
  108         EXT2_FT_CHRDEV,         /* DT_CHR */
  109         EXT2_FT_UNKNOWN,        /* unused */
  110         EXT2_FT_DIR,            /* DT_DIR */
  111         EXT2_FT_UNKNOWN,        /* unused */
  112         EXT2_FT_BLKDEV,         /* DT_BLK */
  113         EXT2_FT_UNKNOWN,        /* unused */
  114         EXT2_FT_REG_FILE,       /* DT_REG */
  115         EXT2_FT_UNKNOWN,        /* unused */
  116         EXT2_FT_SYMLINK,        /* DT_LNK */
  117         EXT2_FT_UNKNOWN,        /* unused */
  118         EXT2_FT_SOCK,           /* DT_SOCK */
  119         EXT2_FT_UNKNOWN,        /* unused */
  120         EXT2_FT_UNKNOWN,        /* DT_WHT */
  121 };
  122 #define DTTOFT(dt) \
  123     ((dt) < nitems(dt_to_ext2_ft) ? dt_to_ext2_ft[(dt)] : EXT2_FT_UNKNOWN)
  124 
  125 static int      ext2_check_direntry(struct vnode *dp,
  126                     struct ext2fs_direct_2 *de, int entryoffsetinblock);
  127 static int      ext2_is_dot_entry(struct componentname *cnp);
  128 static int      ext2_lookup_ino(struct vnode *vdp, struct vnode **vpp,
  129                     struct componentname *cnp, ino_t *dd_ino);
  130 
  131 static int
  132 ext2_is_dot_entry(struct componentname *cnp)
  133 {
  134         if (cnp->cn_namelen <= 2 && cnp->cn_nameptr[0] == '.' &&
  135             (cnp->cn_nameptr[1] == '.' || cnp->cn_nameptr[1] == '\0'))
  136                 return (1);
  137         return (0);
  138 }
  139 
  140 /*
  141  * Vnode op for reading directories.
  142  */
  143 int
  144 ext2_readdir(struct vop_readdir_args *ap)
  145 {
  146         struct vnode *vp = ap->a_vp;
  147         struct uio *uio = ap->a_uio;
  148         struct buf *bp;
  149         struct inode *ip;
  150         struct ext2fs_direct_2 *dp, *edp;
  151         uint64_t *cookies;
  152         struct dirent dstdp;
  153         off_t offset, startoffset;
  154         size_t readcnt, skipcnt;
  155         ssize_t startresid;
  156         u_int ncookies;
  157         int DIRBLKSIZ = VTOI(ap->a_vp)->i_e2fs->e2fs_bsize;
  158         int error;
  159 
  160         if (uio->uio_offset < 0)
  161                 return (EINVAL);
  162         ip = VTOI(vp);
  163         if (ap->a_ncookies != NULL) {
  164                 if (uio->uio_resid < 0)
  165                         ncookies = 0;
  166                 else
  167                         ncookies = uio->uio_resid;
  168                 if (uio->uio_offset >= ip->i_size)
  169                         ncookies = 0;
  170                 else if (ip->i_size - uio->uio_offset < ncookies)
  171                         ncookies = ip->i_size - uio->uio_offset;
  172                 ncookies = ncookies / (offsetof(struct ext2fs_direct_2,
  173                     e2d_namlen) + 4) + 1;
  174                 cookies = malloc(ncookies * sizeof(*cookies), M_TEMP, M_WAITOK);
  175                 *ap->a_ncookies = ncookies;
  176                 *ap->a_cookies = cookies;
  177         } else {
  178                 ncookies = 0;
  179                 cookies = NULL;
  180         }
  181         offset = startoffset = uio->uio_offset;
  182         startresid = uio->uio_resid;
  183         error = 0;
  184         while (error == 0 && uio->uio_resid > 0 &&
  185             uio->uio_offset < ip->i_size) {
  186                 error = ext2_blkatoff(vp, uio->uio_offset, NULL, &bp);
  187                 if (error)
  188                         break;
  189                 if (bp->b_offset + bp->b_bcount > ip->i_size)
  190                         readcnt = ip->i_size - bp->b_offset;
  191                 else
  192                         readcnt = bp->b_bcount;
  193                 skipcnt = (size_t)(uio->uio_offset - bp->b_offset) &
  194                     ~(size_t)(DIRBLKSIZ - 1);
  195                 offset = bp->b_offset + skipcnt;
  196                 dp = (struct ext2fs_direct_2 *)&bp->b_data[skipcnt];
  197                 edp = (struct ext2fs_direct_2 *)&bp->b_data[readcnt];
  198                 while (error == 0 && uio->uio_resid > 0 && dp < edp) {
  199                         if (le16toh(dp->e2d_reclen) <= offsetof(struct ext2fs_direct_2,
  200                             e2d_namlen) || (caddr_t)dp + le16toh(dp->e2d_reclen) >
  201                             (caddr_t)edp) {
  202                                 error = EIO;
  203                                 break;
  204                         }
  205                         /*-
  206                          * "New" ext2fs directory entries differ in 3 ways
  207                          * from ufs on-disk ones:
  208                          * - the name is not necessarily NUL-terminated.
  209                          * - the file type field always exists and always
  210                          *   follows the name length field.
  211                          * - the file type is encoded in a different way.
  212                          *
  213                          * "Old" ext2fs directory entries need no special
  214                          * conversions, since they are binary compatible
  215                          * with "new" entries having a file type of 0 (i.e.,
  216                          * EXT2_FT_UNKNOWN).  Splitting the old name length
  217                          * field didn't make a mess like it did in ufs,
  218                          * because ext2fs uses a machine-independent disk
  219                          * layout.
  220                          */
  221                         dstdp.d_namlen = dp->e2d_namlen;
  222                         dstdp.d_type = FTTODT(dp->e2d_type);
  223                         if (offsetof(struct ext2fs_direct_2, e2d_namlen) +
  224                             dstdp.d_namlen > le16toh(dp->e2d_reclen)) {
  225                                 error = EIO;
  226                                 break;
  227                         }
  228                         if (offset < startoffset || le32toh(dp->e2d_ino) == 0)
  229                                 goto nextentry;
  230                         dstdp.d_fileno = le32toh(dp->e2d_ino);
  231                         dstdp.d_reclen = GENERIC_DIRSIZ(&dstdp);
  232                         bcopy(dp->e2d_name, dstdp.d_name, dstdp.d_namlen);
  233                         /* NOTE: d_off is the offset of the *next* entry. */
  234                         dstdp.d_off = offset + le16toh(dp->e2d_reclen);
  235                         dirent_terminate(&dstdp);
  236                         if (dstdp.d_reclen > uio->uio_resid) {
  237                                 if (uio->uio_resid == startresid)
  238                                         error = EINVAL;
  239                                 else
  240                                         error = EJUSTRETURN;
  241                                 break;
  242                         }
  243                         /* Advance dp. */
  244                         error = uiomove((caddr_t)&dstdp, dstdp.d_reclen, uio);
  245                         if (error)
  246                                 break;
  247                         if (cookies != NULL) {
  248                                 KASSERT(ncookies > 0,
  249                                     ("ext2_readdir: cookies buffer too small"));
  250                                 *cookies = offset + le16toh(dp->e2d_reclen);
  251                                 cookies++;
  252                                 ncookies--;
  253                         }
  254 nextentry:
  255                         offset += le16toh(dp->e2d_reclen);
  256                         dp = (struct ext2fs_direct_2 *)((caddr_t)dp +
  257                             le16toh(dp->e2d_reclen));
  258                 }
  259                 bqrelse(bp);
  260                 uio->uio_offset = offset;
  261         }
  262         /* We need to correct uio_offset. */
  263         uio->uio_offset = offset;
  264         if (error == EJUSTRETURN)
  265                 error = 0;
  266         if (ap->a_ncookies != NULL) {
  267                 if (error == 0) {
  268                         *ap->a_ncookies -= ncookies;
  269                 } else {
  270                         free(*ap->a_cookies, M_TEMP);
  271                         *ap->a_ncookies = 0;
  272                         *ap->a_cookies = NULL;
  273                 }
  274         }
  275         if (error == 0 && ap->a_eofflag)
  276                 *ap->a_eofflag = ip->i_size <= uio->uio_offset;
  277         return (error);
  278 }
  279 
  280 /*
  281  * Convert a component of a pathname into a pointer to a locked inode.
  282  * This is a very central and rather complicated routine.
  283  * If the file system is not maintained in a strict tree hierarchy,
  284  * this can result in a deadlock situation (see comments in code below).
  285  *
  286  * The cnp->cn_nameiop argument is LOOKUP, CREATE, RENAME, or DELETE depending
  287  * on whether the name is to be looked up, created, renamed, or deleted.
  288  * When CREATE, RENAME, or DELETE is specified, information usable in
  289  * creating, renaming, or deleting a directory entry may be calculated.
  290  * If flag has LOCKPARENT or'ed into it and the target of the pathname
  291  * exists, lookup returns both the target and its parent directory locked.
  292  * When creating or renaming and LOCKPARENT is specified, the target may
  293  * not be ".".  When deleting and LOCKPARENT is specified, the target may
  294  * be "."., but the caller must check to ensure it does an vrele and vput
  295  * instead of two vputs.
  296  *
  297  * Overall outline of ext2_lookup:
  298  *
  299  *      search for name in directory, to found or notfound
  300  * notfound:
  301  *      if creating, return locked directory, leaving info on available slots
  302  *      else return error
  303  * found:
  304  *      if at end of path and deleting, return information to allow delete
  305  *      if at end of path and rewriting (RENAME and LOCKPARENT), lock target
  306  *        inode and return info to allow rewrite
  307  *      if not at end, add name to cache; if at end and neither creating
  308  *        nor deleting, add name to cache
  309  */
  310 int
  311 ext2_lookup(struct vop_cachedlookup_args *ap)
  312 {
  313 
  314         return (ext2_lookup_ino(ap->a_dvp, ap->a_vpp, ap->a_cnp, NULL));
  315 }
  316 
  317 static int
  318 ext2_lookup_ino(struct vnode *vdp, struct vnode **vpp, struct componentname *cnp,
  319     ino_t *dd_ino)
  320 {
  321         struct inode *dp;               /* inode for directory being searched */
  322         struct buf *bp;                 /* a buffer of directory entries */
  323         struct ext2fs_direct_2 *ep;     /* the current directory entry */
  324         int entryoffsetinblock;         /* offset of ep in bp's buffer */
  325         struct ext2fs_searchslot ss;
  326         doff_t i_diroff;                /* cached i_diroff value */
  327         doff_t i_offset;                /* cached i_offset value */
  328         int numdirpasses;               /* strategy for directory search */
  329         doff_t endsearch;               /* offset to end directory search */
  330         doff_t prevoff;                 /* prev entry dp->i_offset */
  331         struct vnode *pdp;              /* saved dp during symlink work */
  332         struct vnode *tdp;              /* returned by VFS_VGET */
  333         doff_t enduseful;               /* pointer past last used dir slot */
  334         u_long bmask;                   /* block offset mask */
  335         int error;
  336         struct ucred *cred = cnp->cn_cred;
  337         int flags = cnp->cn_flags;
  338         int nameiop = cnp->cn_nameiop;
  339         ino_t ino, ino1;
  340         int ltype;
  341         int entry_found = 0;
  342 
  343         int DIRBLKSIZ = VTOI(vdp)->i_e2fs->e2fs_bsize;
  344 
  345         if (vpp != NULL)
  346                 *vpp = NULL;
  347 
  348         dp = VTOI(vdp);
  349         bmask = VFSTOEXT2(vdp->v_mount)->um_mountp->mnt_stat.f_iosize - 1;
  350 restart:
  351         bp = NULL;
  352         ss.slotoffset = -1;
  353 
  354         /*
  355          * We now have a segment name to search for, and a directory to search.
  356          *
  357          * Suppress search for slots unless creating
  358          * file and at end of pathname, in which case
  359          * we watch for a place to put the new file in
  360          * case it doesn't already exist.
  361          */
  362         i_diroff = dp->i_diroff;
  363         ss.slotstatus = FOUND;
  364         ss.slotfreespace = ss.slotsize = ss.slotneeded = 0;
  365         if ((nameiop == CREATE || nameiop == RENAME) &&
  366             (flags & ISLASTCN)) {
  367                 ss.slotstatus = NONE;
  368                 ss.slotneeded = EXT2_DIR_REC_LEN(cnp->cn_namelen);
  369                 /*
  370                  * was ss.slotneeded = (sizeof(struct direct) - MAXNAMLEN +
  371                  * cnp->cn_namelen + 3) &~ 3;
  372                  */
  373         }
  374         /*
  375          * Try to lookup dir entry using htree directory index.
  376          *
  377          * If we got an error or we want to find '.' or '..' entry,
  378          * we will fall back to linear search.
  379          */
  380         if (!ext2_is_dot_entry(cnp) && ext2_htree_has_idx(dp)) {
  381                 numdirpasses = 1;
  382                 entryoffsetinblock = 0;
  383                 switch (ext2_htree_lookup(dp, cnp->cn_nameptr, cnp->cn_namelen,
  384                     &bp, &entryoffsetinblock, &i_offset, &prevoff,
  385                     &enduseful, &ss)) {
  386                 case 0:
  387                         ep = (struct ext2fs_direct_2 *)((char *)bp->b_data +
  388                             (i_offset & bmask));
  389                         goto foundentry;
  390                 case ENOENT:
  391                         i_offset = roundup2(dp->i_size, DIRBLKSIZ);
  392                         goto notfound;
  393                 default:
  394                         /*
  395                          * Something failed; just fallback to do a linear
  396                          * search.
  397                          */
  398                         break;
  399                 }
  400         }
  401 
  402         /*
  403          * If there is cached information on a previous search of
  404          * this directory, pick up where we last left off.
  405          * We cache only lookups as these are the most common
  406          * and have the greatest payoff. Caching CREATE has little
  407          * benefit as it usually must search the entire directory
  408          * to determine that the entry does not exist. Caching the
  409          * location of the last DELETE or RENAME has not reduced
  410          * profiling time and hence has been removed in the interest
  411          * of simplicity.
  412          */
  413         if (nameiop != LOOKUP || i_diroff == 0 ||
  414             i_diroff > dp->i_size) {
  415                 entryoffsetinblock = 0;
  416                 i_offset = 0;
  417                 numdirpasses = 1;
  418         } else {
  419                 i_offset = i_diroff;
  420                 if ((entryoffsetinblock = i_offset & bmask) &&
  421                     (error = ext2_blkatoff(vdp, (off_t)i_offset, NULL,
  422                     &bp)))
  423                         return (error);
  424                 numdirpasses = 2;
  425                 nchstats.ncs_2passes++;
  426         }
  427         prevoff = i_offset;
  428         endsearch = roundup2(dp->i_size, DIRBLKSIZ);
  429         enduseful = 0;
  430 
  431 searchloop:
  432         while (i_offset < endsearch) {
  433                 /*
  434                  * If necessary, get the next directory block.
  435                  */
  436                 if (bp != NULL)
  437                         brelse(bp);
  438                 error = ext2_blkatoff(vdp, (off_t)i_offset, NULL, &bp);
  439                 if (error != 0)
  440                         return (error);
  441 
  442                 entryoffsetinblock = 0;
  443                 if (ss.slotstatus == NONE) {
  444                         ss.slotoffset = -1;
  445                         ss.slotfreespace = 0;
  446                 }
  447 
  448                 error = ext2_search_dirblock(dp, bp->b_data, &entry_found,
  449                     cnp->cn_nameptr, cnp->cn_namelen,
  450                     &entryoffsetinblock, &i_offset, &prevoff,
  451                     &enduseful, &ss);
  452                 if (error != 0) {
  453                         brelse(bp);
  454                         return (error);
  455                 }
  456                 if (entry_found) {
  457                         ep = (struct ext2fs_direct_2 *)((char *)bp->b_data +
  458                             (entryoffsetinblock & bmask));
  459 foundentry:
  460                         ino = le32toh(ep->e2d_ino);
  461                         goto found;
  462                 }
  463         }
  464 notfound:
  465         /*
  466          * If we started in the middle of the directory and failed
  467          * to find our target, we must check the beginning as well.
  468          */
  469         if (numdirpasses == 2) {
  470                 numdirpasses--;
  471                 i_offset = 0;
  472                 endsearch = i_diroff;
  473                 goto searchloop;
  474         }
  475         if (bp != NULL)
  476                 brelse(bp);
  477         /*
  478          * If creating, and at end of pathname and current
  479          * directory has not been removed, then can consider
  480          * allowing file to be created.
  481          */
  482         if ((nameiop == CREATE || nameiop == RENAME) &&
  483             (flags & ISLASTCN) && dp->i_nlink != 0) {
  484                 /*
  485                  * Access for write is interpreted as allowing
  486                  * creation of files in the directory.
  487                  */
  488                 if ((error = VOP_ACCESS(vdp, VWRITE, cred, curthread)) != 0)
  489                         return (error);
  490                 /*
  491                  * Return an indication of where the new directory
  492                  * entry should be put.  If we didn't find a slot,
  493                  * then set dp->i_count to 0 indicating
  494                  * that the new slot belongs at the end of the
  495                  * directory. If we found a slot, then the new entry
  496                  * can be put in the range from dp->i_offset to
  497                  * dp->i_offset + dp->i_count.
  498                  */
  499                 if (ss.slotstatus == NONE) {
  500                         dp->i_offset = roundup2(dp->i_size, DIRBLKSIZ);
  501                         dp->i_count = 0;
  502                         enduseful = dp->i_offset;
  503                 } else {
  504                         dp->i_offset = ss.slotoffset;
  505                         dp->i_count = ss.slotsize;
  506                         if (enduseful < ss.slotoffset + ss.slotsize)
  507                                 enduseful = ss.slotoffset + ss.slotsize;
  508                 }
  509                 dp->i_endoff = roundup2(enduseful, DIRBLKSIZ);
  510                 /*
  511                  * We return with the directory locked, so that
  512                  * the parameters we set up above will still be
  513                  * valid if we actually decide to do a direnter().
  514                  * We return ni_vp == NULL to indicate that the entry
  515                  * does not currently exist; we leave a pointer to
  516                  * the (locked) directory inode in ndp->ni_dvp.
  517                  *
  518                  * NB - if the directory is unlocked, then this
  519                  * information cannot be used.
  520                  */
  521                 return (EJUSTRETURN);
  522         }
  523         /*
  524          * Insert name into cache (as non-existent) if appropriate.
  525          */
  526         if ((cnp->cn_flags & MAKEENTRY) != 0)
  527                 cache_enter(vdp, NULL, cnp);
  528         return (ENOENT);
  529 
  530 found:
  531         if (dd_ino != NULL)
  532                 *dd_ino = ino;
  533         if (numdirpasses == 2)
  534                 nchstats.ncs_pass2++;
  535         /*
  536          * Check that directory length properly reflects presence
  537          * of this entry.
  538          */
  539         if (entryoffsetinblock + EXT2_DIR_REC_LEN(ep->e2d_namlen) >
  540             dp->i_size) {
  541                 ext2_dirbad(dp, i_offset, "i_size too small");
  542                 dp->i_size = entryoffsetinblock + EXT2_DIR_REC_LEN(ep->e2d_namlen);
  543                 dp->i_flag |= IN_CHANGE | IN_UPDATE;
  544         }
  545         brelse(bp);
  546 
  547         /*
  548          * Found component in pathname.
  549          * If the final component of path name, save information
  550          * in the cache as to where the entry was found.
  551          */
  552         if ((flags & ISLASTCN) && nameiop == LOOKUP)
  553                 dp->i_diroff = rounddown2(i_offset, DIRBLKSIZ);
  554         /*
  555          * If deleting, and at end of pathname, return
  556          * parameters which can be used to remove file.
  557          */
  558         if (nameiop == DELETE && (flags & ISLASTCN)) {
  559                 if (flags & LOCKPARENT)
  560                         ASSERT_VOP_ELOCKED(vdp, __FUNCTION__);
  561                 /*
  562                  * Write access to directory required to delete files.
  563                  */
  564                 if ((error = VOP_ACCESS(vdp, VWRITE, cred, curthread)) != 0)
  565                         return (error);
  566                 /*
  567                  * Return pointer to current entry in dp->i_offset,
  568                  * and distance past previous entry (if there
  569                  * is a previous entry in this block) in dp->i_count.
  570                  * Save directory inode pointer in ndp->ni_dvp for dirremove().
  571                  *
  572                  * Technically we shouldn't be setting these in the
  573                  * WANTPARENT case (first lookup in rename()), but any
  574                  * lookups that will result in directory changes will
  575                  * overwrite these.
  576                  */
  577                 dp->i_offset = i_offset;
  578                 if ((dp->i_offset & (DIRBLKSIZ - 1)) == 0)
  579                         dp->i_count = 0;
  580                 else
  581                         dp->i_count = dp->i_offset - prevoff;
  582                 if (dd_ino != NULL)
  583                         return (0);
  584                 if (dp->i_number == ino) {
  585                         VREF(vdp);
  586                         *vpp = vdp;
  587                         return (0);
  588                 }
  589                 if ((error = VFS_VGET(vdp->v_mount, ino, LK_EXCLUSIVE,
  590                     &tdp)) != 0)
  591                         return (error);
  592                 /*
  593                  * If directory is "sticky", then user must own
  594                  * the directory, or the file in it, else she
  595                  * may not delete it (unless she's root). This
  596                  * implements append-only directories.
  597                  */
  598                 if ((dp->i_mode & ISVTX) &&
  599                     cred->cr_uid != 0 &&
  600                     cred->cr_uid != dp->i_uid &&
  601                     VTOI(tdp)->i_uid != cred->cr_uid) {
  602                         vput(tdp);
  603                         return (EPERM);
  604                 }
  605                 *vpp = tdp;
  606                 return (0);
  607         }
  608 
  609         /*
  610          * If rewriting (RENAME), return the inode and the
  611          * information required to rewrite the present directory
  612          * Must get inode of directory entry to verify it's a
  613          * regular file, or empty directory.
  614          */
  615         if (nameiop == RENAME && (flags & ISLASTCN)) {
  616                 if ((error = VOP_ACCESS(vdp, VWRITE, cred, curthread)) != 0)
  617                         return (error);
  618                 /*
  619                  * Careful about locking second inode.
  620                  * This can only occur if the target is ".".
  621                  */
  622                 dp->i_offset = i_offset;
  623                 if (dp->i_number == ino)
  624                         return (EISDIR);
  625                 if (dd_ino != NULL)
  626                         return (0);
  627                 if ((error = VFS_VGET(vdp->v_mount, ino, LK_EXCLUSIVE,
  628                     &tdp)) != 0)
  629                         return (error);
  630                 *vpp = tdp;
  631                 return (0);
  632         }
  633         if (dd_ino != NULL)
  634                 return (0);
  635 
  636         /*
  637          * Step through the translation in the name.  We do not `vput' the
  638          * directory because we may need it again if a symbolic link
  639          * is relative to the current directory.  Instead we save it
  640          * unlocked as "pdp".  We must get the target inode before unlocking
  641          * the directory to insure that the inode will not be removed
  642          * before we get it.  We prevent deadlock by always fetching
  643          * inodes from the root, moving down the directory tree. Thus
  644          * when following backward pointers ".." we must unlock the
  645          * parent directory before getting the requested directory.
  646          * There is a potential race condition here if both the current
  647          * and parent directories are removed before the VFS_VGET for the
  648          * inode associated with ".." returns.  We hope that this occurs
  649          * infrequently since we cannot avoid this race condition without
  650          * implementing a sophisticated deadlock detection algorithm.
  651          * Note also that this simple deadlock detection scheme will not
  652          * work if the file system has any hard links other than ".."
  653          * that point backwards in the directory structure.
  654          */
  655         pdp = vdp;
  656         if (flags & ISDOTDOT) {
  657                 error = vn_vget_ino(pdp, ino, cnp->cn_lkflags, &tdp);
  658                 if (VN_IS_DOOMED(pdp)) {
  659                         if (error == 0)
  660                                 vput(tdp);
  661                         error = ENOENT;
  662                 }
  663                 if (error)
  664                         return (error);
  665                 /*
  666                  * Recheck that ".." entry in the vdp directory points
  667                  * to the inode we looked up before vdp lock was
  668                  * dropped.
  669                  */
  670                 error = ext2_lookup_ino(pdp, NULL, cnp, &ino1);
  671                 if (error) {
  672                         vput(tdp);
  673                         return (error);
  674                 }
  675                 if (ino1 != ino) {
  676                         vput(tdp);
  677                         goto restart;
  678                 }
  679                 *vpp = tdp;
  680         } else if (dp->i_number == ino) {
  681                 VREF(vdp);      /* we want ourself, ie "." */
  682                 /*
  683                  * When we lookup "." we still can be asked to lock it
  684                  * differently.
  685                  */
  686                 ltype = cnp->cn_lkflags & LK_TYPE_MASK;
  687                 if (ltype != VOP_ISLOCKED(vdp)) {
  688                         if (ltype == LK_EXCLUSIVE)
  689                                 vn_lock(vdp, LK_UPGRADE | LK_RETRY);
  690                         else    /* if (ltype == LK_SHARED) */
  691                                 vn_lock(vdp, LK_DOWNGRADE | LK_RETRY);
  692                 }
  693                 *vpp = vdp;
  694         } else {
  695                 if ((error = VFS_VGET(vdp->v_mount, ino, cnp->cn_lkflags,
  696                     &tdp)) != 0)
  697                         return (error);
  698                 *vpp = tdp;
  699         }
  700 
  701         /*
  702          * Insert name into cache if appropriate.
  703          */
  704         if (cnp->cn_flags & MAKEENTRY)
  705                 cache_enter(vdp, *vpp, cnp);
  706         return (0);
  707 }
  708 
  709 int
  710 ext2_search_dirblock(struct inode *ip, void *data, int *foundp,
  711     const char *name, int namelen, int *entryoffsetinblockp,
  712     doff_t *offp, doff_t *prevoffp, doff_t *endusefulp,
  713     struct ext2fs_searchslot *ssp)
  714 {
  715         struct vnode *vdp;
  716         struct ext2fs_direct_2 *ep, *top;
  717         uint32_t bsize = ip->i_e2fs->e2fs_bsize;
  718         int offset = *entryoffsetinblockp;
  719         int namlen;
  720 
  721         vdp = ITOV(ip);
  722 
  723         ep = (struct ext2fs_direct_2 *)((char *)data + offset);
  724         top = (struct ext2fs_direct_2 *)((char *)data + bsize);
  725         while (ep < top) {
  726                 if (ext2_check_direntry(vdp, ep, offset)) {
  727                         int i;
  728 
  729                         ext2_dirbad(ip, *offp, "mangled entry");
  730                         i = bsize - (offset & (bsize - 1));
  731                         *offp += i;
  732                         offset += i;
  733                         ep = (struct ext2fs_direct_2 *)((char *)data + offset);
  734                         continue;
  735                 }
  736 
  737                 /*
  738                  * If an appropriate sized slot has not yet been found,
  739                  * check to see if one is available. Also accumulate space
  740                  * in the current block so that we can determine if
  741                  * compaction is viable.
  742                  */
  743                 if (ssp->slotstatus != FOUND) {
  744                         int size = le16toh(ep->e2d_reclen);
  745 
  746                         if (ep->e2d_ino != 0)
  747                                 size -= EXT2_DIR_REC_LEN(ep->e2d_namlen);
  748                         else if (ext2_is_dirent_tail(ip, ep))
  749                                 size -= sizeof(struct ext2fs_direct_tail);
  750                         if (size > 0) {
  751                                 if (size >= ssp->slotneeded) {
  752                                         ssp->slotstatus = FOUND;
  753                                         ssp->slotoffset = *offp;
  754                                         ssp->slotsize = le16toh(ep->e2d_reclen);
  755                                 } else if (ssp->slotstatus == NONE) {
  756                                         ssp->slotfreespace += size;
  757                                         if (ssp->slotoffset == -1)
  758                                                 ssp->slotoffset = *offp;
  759                                         if (ssp->slotfreespace >= ssp->slotneeded) {
  760                                                 ssp->slotstatus = COMPACT;
  761                                                 ssp->slotsize = *offp +
  762                                                     le16toh(ep->e2d_reclen) -
  763                                                     ssp->slotoffset;
  764                                         }
  765                                 }
  766                         }
  767                 }
  768                 /*
  769                  * Check for a name match.
  770                  */
  771                 if (ep->e2d_ino != 0) {
  772                         namlen = ep->e2d_namlen;
  773                         if (namlen == namelen &&
  774                             !bcmp(name, ep->e2d_name, (unsigned)namlen)) {
  775                                 /*
  776                                  * Save directory entry's inode number and
  777                                  * reclen in ndp->ni_ufs area, and release
  778                                  * directory buffer.
  779                                  */
  780                                 *foundp = 1;
  781                                 return (0);
  782                         }
  783                 }
  784                 *prevoffp = *offp;
  785                 *offp += le16toh(ep->e2d_reclen);
  786                 offset += le16toh(ep->e2d_reclen);
  787                 *entryoffsetinblockp = offset;
  788                 if (ep->e2d_ino != 0)
  789                         *endusefulp = *offp;
  790                 /*
  791                  * Get pointer to the next entry.
  792                  */
  793                 ep = (struct ext2fs_direct_2 *)((char *)data + offset);
  794         }
  795 
  796         return (0);
  797 }
  798 
  799 void
  800 ext2_dirbad(struct inode *ip, doff_t offset, char *how)
  801 {
  802         struct mount *mp;
  803 
  804         mp = ITOV(ip)->v_mount;
  805         if ((mp->mnt_flag & MNT_RDONLY) == 0)
  806                 panic("ext2_dirbad: %s: bad dir ino %ju at offset %ld: %s\n",
  807                     mp->mnt_stat.f_mntonname, (uintmax_t)ip->i_number,
  808                     (long)offset, how);
  809         else
  810                 SDT_PROBE4(ext2fs, , trace, ext2_dirbad_error,
  811                     mp->mnt_stat.f_mntonname, ip->i_number, offset, how);
  812 }
  813 
  814 /*
  815  * Do consistency checking on a directory entry:
  816  *      record length must be multiple of 4
  817  *      entry must fit in rest of its DIRBLKSIZ block
  818  *      record must be large enough to contain entry
  819  *      name is not longer than MAXNAMLEN
  820  *      name must be as long as advertised, and null terminated
  821  */
  822 static int
  823 ext2_check_direntry(struct vnode *dp, struct ext2fs_direct_2 *de,
  824     int entryoffsetinblock)
  825 {
  826         struct m_ext2fs *fs = VTOI(dp)->i_e2fs;
  827         char *error_msg = NULL;
  828 
  829         if (le16toh(de->e2d_reclen) < EXT2_DIR_REC_LEN(1))
  830                 error_msg = "rec_len is smaller than minimal";
  831         else if (le16toh(de->e2d_reclen) % 4 != 0)
  832                 error_msg = "rec_len % 4 != 0";
  833         else if (le16toh(de->e2d_reclen) < EXT2_DIR_REC_LEN(de->e2d_namlen))
  834                 error_msg = "reclen is too small for name_len";
  835         else if (entryoffsetinblock + le16toh(de->e2d_reclen)> fs->e2fs_bsize)
  836                 error_msg = "directory entry across blocks";
  837         else if (le32toh(de->e2d_ino) > fs->e2fs->e2fs_icount)
  838                 error_msg = "directory entry inode out of bounds";
  839 
  840         if (error_msg != NULL) {
  841                 SDT_PROBE5(ext2fs, , trace, ext2_dirbadentry_error,
  842                     error_msg, entryoffsetinblock,
  843                     le32toh(de->e2d_ino), le16toh(de->e2d_reclen),
  844                     de->e2d_namlen);
  845         }
  846         return (error_msg == NULL ? 0 : EINVAL);
  847 }
  848 
  849 /*
  850  * Insert an entry into the fresh directory block.
  851  * Initialize entry tail if the metadata_csum feature is turned on.
  852  */
  853 static int
  854 ext2_add_first_entry(struct vnode *dvp, struct ext2fs_direct_2 *entry,
  855     struct componentname *cnp)
  856 {
  857         struct inode *dp;
  858         struct iovec aiov;
  859         struct uio auio;
  860         char* buf = NULL;
  861         int dirblksize, error;
  862 
  863         dp = VTOI(dvp);
  864         dirblksize = dp->i_e2fs->e2fs_bsize;
  865 
  866         if (dp->i_offset & (dirblksize - 1))
  867                 panic("ext2_add_first_entry: bad directory offset");
  868 
  869         if (EXT2_HAS_RO_COMPAT_FEATURE(dp->i_e2fs,
  870             EXT2F_ROCOMPAT_METADATA_CKSUM)) {
  871                 entry->e2d_reclen = htole16(dirblksize -
  872                     sizeof(struct ext2fs_direct_tail));
  873                 buf = malloc(dirblksize, M_TEMP, M_WAITOK);
  874                 memcpy(buf, entry, EXT2_DIR_REC_LEN(entry->e2d_namlen));
  875                 ext2_init_dirent_tail(EXT2_DIRENT_TAIL(buf, dirblksize));
  876                 ext2_dirent_csum_set(dp, (struct ext2fs_direct_2 *)buf);
  877 
  878                 auio.uio_offset = dp->i_offset;
  879                 auio.uio_resid = dirblksize;
  880                 aiov.iov_len = auio.uio_resid;
  881                 aiov.iov_base = (caddr_t)buf;
  882         } else {
  883                 entry->e2d_reclen = htole16(dirblksize);
  884                 auio.uio_offset = dp->i_offset;
  885                 auio.uio_resid = EXT2_DIR_REC_LEN(entry->e2d_namlen);
  886                 aiov.iov_len = auio.uio_resid;
  887                 aiov.iov_base = (caddr_t)entry;
  888         }
  889 
  890         auio.uio_iov = &aiov;
  891         auio.uio_iovcnt = 1;
  892         auio.uio_rw = UIO_WRITE;
  893         auio.uio_segflg = UIO_SYSSPACE;
  894         auio.uio_td = (struct thread *)0;
  895         error = VOP_WRITE(dvp, &auio, IO_SYNC, cnp->cn_cred);
  896         if (error)
  897                 goto out;
  898 
  899         dp->i_size = roundup2(dp->i_size, dirblksize);
  900         dp->i_flag |= IN_CHANGE;
  901 
  902 out:
  903         free(buf, M_TEMP);
  904         return (error);
  905 
  906 }
  907 
  908 /*
  909  * Write a directory entry after a call to namei, using the parameters
  910  * that it left in nameidata.  The argument ip is the inode which the new
  911  * directory entry will refer to.  Dvp is a pointer to the directory to
  912  * be written, which was left locked by namei. Remaining parameters
  913  * (dp->i_offset, dp->i_count) indicate how the space for the new
  914  * entry is to be obtained.
  915  */
  916 int
  917 ext2_direnter(struct inode *ip, struct vnode *dvp, struct componentname *cnp)
  918 {
  919         struct inode *dp;
  920         struct ext2fs_direct_2 newdir;
  921         int DIRBLKSIZ = ip->i_e2fs->e2fs_bsize;
  922         int error;
  923 
  924         dp = VTOI(dvp);
  925         newdir.e2d_ino = htole32(ip->i_number);
  926         if (EXT2_HAS_INCOMPAT_FEATURE(ip->i_e2fs,
  927             EXT2F_INCOMPAT_FTYPE)) {
  928                 newdir.e2d_namlen = cnp->cn_namelen;
  929                 newdir.e2d_type = DTTOFT(IFTODT(ip->i_mode));
  930         } else
  931                 newdir.e2d_namlen = htole16(cnp->cn_namelen);
  932 
  933         bcopy(cnp->cn_nameptr, newdir.e2d_name, (unsigned)cnp->cn_namelen + 1);
  934 
  935         if (ext2_htree_has_idx(dp)) {
  936                 error = ext2_htree_add_entry(dvp, &newdir, cnp);
  937                 if (error) {
  938                         dp->i_flag &= ~IN_E3INDEX;
  939                         dp->i_flag |= IN_CHANGE | IN_UPDATE;
  940                 }
  941                 return (error);
  942         }
  943 
  944         if (EXT2_HAS_COMPAT_FEATURE(ip->i_e2fs, EXT2F_COMPAT_DIRHASHINDEX) &&
  945             !ext2_htree_has_idx(dp)) {
  946                 if ((dp->i_size / DIRBLKSIZ) == 1 &&
  947                     dp->i_offset == DIRBLKSIZ) {
  948                         /*
  949                          * Making indexed directory when one block is not
  950                          * enough to save all entries.
  951                          */
  952                         return ext2_htree_create_index(dvp, cnp, &newdir);
  953                 }
  954         }
  955 
  956         /*
  957          * If dp->i_count is 0, then namei could find no
  958          * space in the directory. Here, dp->i_offset will
  959          * be on a directory block boundary and we will write the
  960          * new entry into a fresh block.
  961          */
  962         if (dp->i_count == 0)
  963                 return ext2_add_first_entry(dvp, &newdir, cnp);
  964 
  965         error = ext2_add_entry(dvp, &newdir);
  966         if (!error && dp->i_endoff && dp->i_endoff < dp->i_size)
  967                 error = ext2_truncate(dvp, (off_t)dp->i_endoff, IO_SYNC,
  968                     cnp->cn_cred, curthread);
  969         return (error);
  970 }
  971 
  972 /*
  973  * Insert an entry into the directory block.
  974  * Compact the contents.
  975  */
  976 int
  977 ext2_add_entry(struct vnode *dvp, struct ext2fs_direct_2 *entry)
  978 {
  979         struct ext2fs_direct_2 *ep, *nep;
  980         struct inode *dp;
  981         struct buf *bp;
  982         u_int dsize;
  983         int error, loc, newentrysize, spacefree;
  984         char *dirbuf;
  985 
  986         dp = VTOI(dvp);
  987 
  988         /*
  989          * If dp->i_count is non-zero, then namei found space
  990          * for the new entry in the range dp->i_offset to
  991          * dp->i_offset + dp->i_count in the directory.
  992          * To use this space, we may have to compact the entries located
  993          * there, by copying them together towards the beginning of the
  994          * block, leaving the free space in one usable chunk at the end.
  995          */
  996 
  997         /*
  998          * Increase size of directory if entry eats into new space.
  999          * This should never push the size past a new multiple of
 1000          * DIRBLKSIZE.
 1001          *
 1002          * N.B. - THIS IS AN ARTIFACT OF 4.2 AND SHOULD NEVER HAPPEN.
 1003          */
 1004         if (dp->i_offset + dp->i_count > dp->i_size)
 1005                 dp->i_size = dp->i_offset + dp->i_count;
 1006         /*
 1007          * Get the block containing the space for the new directory entry.
 1008          */
 1009         if ((error = ext2_blkatoff(dvp, (off_t)dp->i_offset, &dirbuf,
 1010             &bp)) != 0)
 1011                 return (error);
 1012         /*
 1013          * Find space for the new entry. In the simple case, the entry at
 1014          * offset base will have the space. If it does not, then namei
 1015          * arranged that compacting the region dp->i_offset to
 1016          * dp->i_offset + dp->i_count would yield the
 1017          * space.
 1018          */
 1019         newentrysize = EXT2_DIR_REC_LEN(entry->e2d_namlen);
 1020         ep = (struct ext2fs_direct_2 *)dirbuf;
 1021         dsize = EXT2_DIR_REC_LEN(ep->e2d_namlen);
 1022         spacefree = le16toh(ep->e2d_reclen) - dsize;
 1023         for (loc = le16toh(ep->e2d_reclen); loc < dp->i_count; ) {
 1024                 nep = (struct ext2fs_direct_2 *)(dirbuf + loc);
 1025                 if (le32toh(ep->e2d_ino)) {
 1026                         /* trim the existing slot */
 1027                         ep->e2d_reclen = htole16(dsize);
 1028                         ep = (struct ext2fs_direct_2 *)((char *)ep + dsize);
 1029                 } else {
 1030                         /* overwrite; nothing there; header is ours */
 1031                         spacefree += dsize;
 1032                 }
 1033                 dsize = EXT2_DIR_REC_LEN(nep->e2d_namlen);
 1034                 spacefree += le16toh(nep->e2d_reclen) - dsize;
 1035                 loc += le16toh(nep->e2d_reclen);
 1036                 bcopy((caddr_t)nep, (caddr_t)ep, dsize);
 1037         }
 1038         /*
 1039          * Update the pointer fields in the previous entry (if any),
 1040          * copy in the new entry, and write out the block.
 1041          */
 1042         if (ep->e2d_ino == 0) {
 1043                 if (spacefree + dsize < newentrysize)
 1044                         panic("ext2_direnter: compact1");
 1045                 entry->e2d_reclen = htole16(spacefree + dsize);
 1046         } else {
 1047                 if (spacefree < newentrysize)
 1048                         panic("ext2_direnter: compact2");
 1049                 entry->e2d_reclen = htole16(spacefree);
 1050                 ep->e2d_reclen = htole16(dsize);
 1051                 ep = (struct ext2fs_direct_2 *)((char *)ep + dsize);
 1052         }
 1053         bcopy((caddr_t)entry, (caddr_t)ep, (u_int)newentrysize);
 1054         ext2_dirent_csum_set(dp, (struct ext2fs_direct_2 *)bp->b_data);
 1055         if (DOINGASYNC(dvp)) {
 1056                 bdwrite(bp);
 1057                 error = 0;
 1058         } else {
 1059                 error = bwrite(bp);
 1060         }
 1061         dp->i_flag |= IN_CHANGE | IN_UPDATE;
 1062         return (error);
 1063 }
 1064 
 1065 /*
 1066  * Remove a directory entry after a call to namei, using
 1067  * the parameters which it left in nameidata. The entry
 1068  * dp->i_offset contains the offset into the directory of the
 1069  * entry to be eliminated.  The dp->i_count field contains the
 1070  * size of the previous record in the directory.  If this
 1071  * is 0, the first entry is being deleted, so we need only
 1072  * zero the inode number to mark the entry as free.  If the
 1073  * entry is not the first in the directory, we must reclaim
 1074  * the space of the now empty record by adding the record size
 1075  * to the size of the previous entry.
 1076  */
 1077 int
 1078 ext2_dirremove(struct vnode *dvp, struct componentname *cnp)
 1079 {
 1080         struct inode *dp;
 1081         struct ext2fs_direct_2 *ep, *rep;
 1082         struct buf *bp;
 1083         int error;
 1084 
 1085         dp = VTOI(dvp);
 1086         if (dp->i_count == 0) {
 1087                 /*
 1088                  * First entry in block: set d_ino to zero.
 1089                  */
 1090                 if ((error =
 1091                     ext2_blkatoff(dvp, (off_t)dp->i_offset, (char **)&ep,
 1092                     &bp)) != 0)
 1093                         return (error);
 1094                 ep->e2d_ino = 0;
 1095                 ext2_dirent_csum_set(dp, (struct ext2fs_direct_2 *)bp->b_data);
 1096                 error = bwrite(bp);
 1097                 dp->i_flag |= IN_CHANGE | IN_UPDATE;
 1098                 return (error);
 1099         }
 1100         /*
 1101          * Collapse new free space into previous entry.
 1102          */
 1103         if ((error = ext2_blkatoff(dvp, (off_t)(dp->i_offset - dp->i_count),
 1104             (char **)&ep, &bp)) != 0)
 1105                 return (error);
 1106 
 1107         /* Set 'rep' to the entry being removed. */
 1108         if (dp->i_count == 0)
 1109                 rep = ep;
 1110         else
 1111                 rep = (struct ext2fs_direct_2 *)((char *)ep +
 1112                     le16toh(ep->e2d_reclen));
 1113         ep->e2d_reclen += rep->e2d_reclen;
 1114         ext2_dirent_csum_set(dp, (struct ext2fs_direct_2 *)bp->b_data);
 1115         if (DOINGASYNC(dvp) && dp->i_count != 0)
 1116                 bdwrite(bp);
 1117         else
 1118                 error = bwrite(bp);
 1119         dp->i_flag |= IN_CHANGE | IN_UPDATE;
 1120         return (error);
 1121 }
 1122 
 1123 /*
 1124  * Rewrite an existing directory entry to point at the inode
 1125  * supplied.  The parameters describing the directory entry are
 1126  * set up by a call to namei.
 1127  */
 1128 int
 1129 ext2_dirrewrite(struct inode *dp, struct inode *ip, struct componentname *cnp)
 1130 {
 1131         struct buf *bp;
 1132         struct ext2fs_direct_2 *ep;
 1133         struct vnode *vdp = ITOV(dp);
 1134         int error;
 1135 
 1136         if ((error = ext2_blkatoff(vdp, (off_t)dp->i_offset, (char **)&ep,
 1137             &bp)) != 0)
 1138                 return (error);
 1139         ep->e2d_ino = htole32(ip->i_number);
 1140         if (EXT2_HAS_INCOMPAT_FEATURE(ip->i_e2fs,
 1141             EXT2F_INCOMPAT_FTYPE))
 1142                 ep->e2d_type = DTTOFT(IFTODT(ip->i_mode));
 1143         else
 1144                 ep->e2d_type = EXT2_FT_UNKNOWN;
 1145         ext2_dirent_csum_set(dp, (struct ext2fs_direct_2 *)bp->b_data);
 1146         error = bwrite(bp);
 1147         dp->i_flag |= IN_CHANGE | IN_UPDATE;
 1148         return (error);
 1149 }
 1150 
 1151 /*
 1152  * Check if a directory is empty or not.
 1153  * Inode supplied must be locked.
 1154  *
 1155  * Using a struct dirtemplate here is not precisely
 1156  * what we want, but better than using a struct direct.
 1157  *
 1158  * NB: does not handle corrupted directories.
 1159  */
 1160 int
 1161 ext2_dirempty(struct inode *ip, ino_t parentino, struct ucred *cred)
 1162 {
 1163         off_t off;
 1164         struct dirtemplate dbuf;
 1165         struct ext2fs_direct_2 *dp = (struct ext2fs_direct_2 *)&dbuf;
 1166         int error, namlen;
 1167         ssize_t count;
 1168 #define MINDIRSIZ (sizeof(struct dirtemplate) / 2)
 1169 
 1170         for (off = 0; off < ip->i_size; off += le16toh(dp->e2d_reclen)) {
 1171                 error = vn_rdwr(UIO_READ, ITOV(ip), (caddr_t)dp, MINDIRSIZ,
 1172                     off, UIO_SYSSPACE, IO_NODELOCKED | IO_NOMACCHECK, cred,
 1173                     NOCRED, &count, (struct thread *)0);
 1174                 /*
 1175                  * Since we read MINDIRSIZ, residual must
 1176                  * be 0 unless we're at end of file.
 1177                  */
 1178                 if (error || count != 0)
 1179                         return (0);
 1180                 /* avoid infinite loops */
 1181                 if (dp->e2d_reclen == 0)
 1182                         return (0);
 1183                 /* skip empty entries */
 1184                 if (dp->e2d_ino == 0)
 1185                         continue;
 1186                 /* accept only "." and ".." */
 1187                 namlen = dp->e2d_namlen;
 1188                 if (namlen > 2)
 1189                         return (0);
 1190                 if (dp->e2d_name[0] != '.')
 1191                         return (0);
 1192                 /*
 1193                  * At this point namlen must be 1 or 2.
 1194                  * 1 implies ".", 2 implies ".." if second
 1195                  * char is also "."
 1196                  */
 1197                 if (namlen == 1)
 1198                         continue;
 1199                 if (dp->e2d_name[1] == '.' && le32toh(dp->e2d_ino) == parentino)
 1200                         continue;
 1201                 return (0);
 1202         }
 1203         return (1);
 1204 }
 1205 
 1206 /*
 1207  * Check if source directory is in the path of the target directory.
 1208  * Target is supplied locked, source is unlocked.
 1209  * The target is always vput before returning.
 1210  */
 1211 int
 1212 ext2_checkpath(struct inode *source, struct inode *target, struct ucred *cred)
 1213 {
 1214         struct vnode *vp;
 1215         int error, namlen;
 1216         struct dirtemplate dirbuf;
 1217 
 1218         vp = ITOV(target);
 1219         if (target->i_number == source->i_number) {
 1220                 error = EEXIST;
 1221                 goto out;
 1222         }
 1223         if (target->i_number == EXT2_ROOTINO) {
 1224                 error = 0;
 1225                 goto out;
 1226         }
 1227 
 1228         for (;;) {
 1229                 if (vp->v_type != VDIR) {
 1230                         error = ENOTDIR;
 1231                         break;
 1232                 }
 1233                 error = vn_rdwr(UIO_READ, vp, (caddr_t)&dirbuf,
 1234                     sizeof(struct dirtemplate), (off_t)0, UIO_SYSSPACE,
 1235                     IO_NODELOCKED | IO_NOMACCHECK, cred, NOCRED, NULL,
 1236                     NULL);
 1237                 if (error != 0)
 1238                         break;
 1239                 namlen = dirbuf.dotdot_type;    /* like ufs little-endian */
 1240                 if (namlen != 2 ||
 1241                     dirbuf.dotdot_name[0] != '.' ||
 1242                     dirbuf.dotdot_name[1] != '.') {
 1243                         error = ENOTDIR;
 1244                         break;
 1245                 }
 1246                 if (le32toh(dirbuf.dotdot_ino) == source->i_number) {
 1247                         error = EINVAL;
 1248                         break;
 1249                 }
 1250                 if (le32toh(dirbuf.dotdot_ino) == EXT2_ROOTINO)
 1251                         break;
 1252                 vput(vp);
 1253                 if ((error = VFS_VGET(vp->v_mount, le32toh(dirbuf.dotdot_ino),
 1254                     LK_EXCLUSIVE, &vp)) != 0) {
 1255                         vp = NULL;
 1256                         break;
 1257                 }
 1258         }
 1259 
 1260 out:
 1261         if (error == ENOTDIR)
 1262                 SDT_PROBE2(ext2fs, , lookup, trace, 1,
 1263                     "checkpath: .. not a directory");
 1264         if (vp != NULL)
 1265                 vput(vp);
 1266         return (error);
 1267 }

Cache object: 9f7f2582e9bc92744252df54ea09bf2f


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