The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/fs/ext2fs/ext2_lookup.c

Version: -  FREEBSD  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-2  -  FREEBSD-11-1  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-4  -  FREEBSD-10-3  -  FREEBSD-10-2  -  FREEBSD-10-1  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-3  -  FREEBSD-9-2  -  FREEBSD-9-1  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-4  -  FREEBSD-8-3  -  FREEBSD-8-2  -  FREEBSD-8-1  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-4  -  FREEBSD-7-3  -  FREEBSD-7-2  -  FREEBSD-7-1  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-4  -  FREEBSD-6-3  -  FREEBSD-6-2  -  FREEBSD-6-1  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-5  -  FREEBSD-5-4  -  FREEBSD-5-3  -  FREEBSD-5-2  -  FREEBSD-5-1  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  linux-2.6  -  linux-2.4.22  -  MK83  -  MK84  -  PLAN9  -  DFBSD  -  NETBSD  -  NETBSD5  -  NETBSD4  -  NETBSD3  -  NETBSD20  -  OPENBSD  -  xnu-517  -  xnu-792  -  xnu-792.6.70  -  xnu-1228  -  xnu-1456.1.26  -  xnu-1699.24.8  -  xnu-2050.18.24  -  OPENSOLARIS  -  minix-3-1-1 
SearchContext: -  none  -  3  -  10 

    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: releng/12.0/sys/fs/ext2fs/ext2_lookup.c 341085 2018-11-27 17:58:25Z markj $
   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/sysctl.h>
   57 
   58 #include <ufs/ufs/dir.h>
   59 
   60 #include <fs/ext2fs/fs.h>
   61 #include <fs/ext2fs/inode.h>
   62 #include <fs/ext2fs/ext2_mount.h>
   63 #include <fs/ext2fs/ext2fs.h>
   64 #include <fs/ext2fs/ext2_dinode.h>
   65 #include <fs/ext2fs/ext2_dir.h>
   66 #include <fs/ext2fs/ext2_extern.h>
   67 #include <fs/ext2fs/fs.h>
   68 
   69 #ifdef INVARIANTS
   70 static int dirchk = 1;
   71 #else
   72 static int dirchk = 0;
   73 #endif
   74 
   75 static SYSCTL_NODE(_vfs, OID_AUTO, e2fs, CTLFLAG_RD, 0, "EXT2FS filesystem");
   76 SYSCTL_INT(_vfs_e2fs, OID_AUTO, dircheck, CTLFLAG_RW, &dirchk, 0, "");
   77 
   78 /*
   79    DIRBLKSIZE in ffs is DEV_BSIZE (in most cases 512)
   80    while it is the native blocksize in ext2fs - thus, a #define
   81    is no longer appropriate
   82 */
   83 #undef  DIRBLKSIZ
   84 
   85 static u_char ext2_ft_to_dt[] = {
   86         DT_UNKNOWN,             /* EXT2_FT_UNKNOWN */
   87         DT_REG,                 /* EXT2_FT_REG_FILE */
   88         DT_DIR,                 /* EXT2_FT_DIR */
   89         DT_CHR,                 /* EXT2_FT_CHRDEV */
   90         DT_BLK,                 /* EXT2_FT_BLKDEV */
   91         DT_FIFO,                /* EXT2_FT_FIFO */
   92         DT_SOCK,                /* EXT2_FT_SOCK */
   93         DT_LNK,                 /* EXT2_FT_SYMLINK */
   94 };
   95 #define FTTODT(ft) \
   96     ((ft) < nitems(ext2_ft_to_dt) ? ext2_ft_to_dt[(ft)] : DT_UNKNOWN)
   97 
   98 static u_char dt_to_ext2_ft[] = {
   99         EXT2_FT_UNKNOWN,        /* DT_UNKNOWN */
  100         EXT2_FT_FIFO,           /* DT_FIFO */
  101         EXT2_FT_CHRDEV,         /* DT_CHR */
  102         EXT2_FT_UNKNOWN,        /* unused */
  103         EXT2_FT_DIR,            /* DT_DIR */
  104         EXT2_FT_UNKNOWN,        /* unused */
  105         EXT2_FT_BLKDEV,         /* DT_BLK */
  106         EXT2_FT_UNKNOWN,        /* unused */
  107         EXT2_FT_REG_FILE,       /* DT_REG */
  108         EXT2_FT_UNKNOWN,        /* unused */
  109         EXT2_FT_SYMLINK,        /* DT_LNK */
  110         EXT2_FT_UNKNOWN,        /* unused */
  111         EXT2_FT_SOCK,           /* DT_SOCK */
  112         EXT2_FT_UNKNOWN,        /* unused */
  113         EXT2_FT_UNKNOWN,        /* DT_WHT */
  114 };
  115 #define DTTOFT(dt) \
  116     ((dt) < nitems(dt_to_ext2_ft) ? dt_to_ext2_ft[(dt)] : EXT2_FT_UNKNOWN)
  117 
  118 static int      ext2_dirbadentry(struct vnode *dp, struct ext2fs_direct_2 *de,
  119                     int entryoffsetinblock);
  120 static int      ext2_is_dot_entry(struct componentname *cnp);
  121 static int      ext2_lookup_ino(struct vnode *vdp, struct vnode **vpp,
  122                     struct componentname *cnp, ino_t *dd_ino);
  123 
  124 static int
  125 ext2_is_dot_entry(struct componentname *cnp)
  126 {
  127         if (cnp->cn_namelen <= 2 && cnp->cn_nameptr[0] == '.' &&
  128             (cnp->cn_nameptr[1] == '.' || cnp->cn_nameptr[1] == '\0'))
  129                 return (1);
  130         return (0);
  131 }
  132 
  133 /*
  134  * Vnode op for reading directories.
  135  */
  136 int
  137 ext2_readdir(struct vop_readdir_args *ap)
  138 {
  139         struct vnode *vp = ap->a_vp;
  140         struct uio *uio = ap->a_uio;
  141         struct buf *bp;
  142         struct inode *ip;
  143         struct ext2fs_direct_2 *dp, *edp;
  144         u_long *cookies;
  145         struct dirent dstdp;
  146         off_t offset, startoffset;
  147         size_t readcnt, skipcnt;
  148         ssize_t startresid;
  149         u_int ncookies;
  150         int DIRBLKSIZ = VTOI(ap->a_vp)->i_e2fs->e2fs_bsize;
  151         int error;
  152 
  153         if (uio->uio_offset < 0)
  154                 return (EINVAL);
  155         ip = VTOI(vp);
  156         if (ap->a_ncookies != NULL) {
  157                 if (uio->uio_resid < 0)
  158                         ncookies = 0;
  159                 else
  160                         ncookies = uio->uio_resid;
  161                 if (uio->uio_offset >= ip->i_size)
  162                         ncookies = 0;
  163                 else if (ip->i_size - uio->uio_offset < ncookies)
  164                         ncookies = ip->i_size - uio->uio_offset;
  165                 ncookies = ncookies / (offsetof(struct ext2fs_direct_2,
  166                     e2d_namlen) + 4) + 1;
  167                 cookies = malloc(ncookies * sizeof(*cookies), M_TEMP, M_WAITOK);
  168                 *ap->a_ncookies = ncookies;
  169                 *ap->a_cookies = cookies;
  170         } else {
  171                 ncookies = 0;
  172                 cookies = NULL;
  173         }
  174         offset = startoffset = uio->uio_offset;
  175         startresid = uio->uio_resid;
  176         error = 0;
  177         while (error == 0 && uio->uio_resid > 0 &&
  178             uio->uio_offset < ip->i_size) {
  179                 error = ext2_blkatoff(vp, uio->uio_offset, NULL, &bp);
  180                 if (error)
  181                         break;
  182                 if (bp->b_offset + bp->b_bcount > ip->i_size)
  183                         readcnt = ip->i_size - bp->b_offset;
  184                 else
  185                         readcnt = bp->b_bcount;
  186                 skipcnt = (size_t)(uio->uio_offset - bp->b_offset) &
  187                     ~(size_t)(DIRBLKSIZ - 1);
  188                 offset = bp->b_offset + skipcnt;
  189                 dp = (struct ext2fs_direct_2 *)&bp->b_data[skipcnt];
  190                 edp = (struct ext2fs_direct_2 *)&bp->b_data[readcnt];
  191                 while (error == 0 && uio->uio_resid > 0 && dp < edp) {
  192                         if (dp->e2d_reclen <= offsetof(struct ext2fs_direct_2,
  193                             e2d_namlen) || (caddr_t)dp + dp->e2d_reclen >
  194                             (caddr_t)edp) {
  195                                 error = EIO;
  196                                 break;
  197                         }
  198                         /*-
  199                          * "New" ext2fs directory entries differ in 3 ways
  200                          * from ufs on-disk ones:
  201                          * - the name is not necessarily NUL-terminated.
  202                          * - the file type field always exists and always
  203                          *   follows the name length field.
  204                          * - the file type is encoded in a different way.
  205                          *
  206                          * "Old" ext2fs directory entries need no special
  207                          * conversions, since they are binary compatible
  208                          * with "new" entries having a file type of 0 (i.e.,
  209                          * EXT2_FT_UNKNOWN).  Splitting the old name length
  210                          * field didn't make a mess like it did in ufs,
  211                          * because ext2fs uses a machine-independent disk
  212                          * layout.
  213                          */
  214                         dstdp.d_namlen = dp->e2d_namlen;
  215                         dstdp.d_type = FTTODT(dp->e2d_type);
  216                         if (offsetof(struct ext2fs_direct_2, e2d_namlen) +
  217                             dstdp.d_namlen > dp->e2d_reclen) {
  218                                 error = EIO;
  219                                 break;
  220                         }
  221                         if (offset < startoffset || dp->e2d_ino == 0)
  222                                 goto nextentry;
  223                         dstdp.d_fileno = dp->e2d_ino;
  224                         dstdp.d_reclen = GENERIC_DIRSIZ(&dstdp);
  225                         bcopy(dp->e2d_name, dstdp.d_name, dstdp.d_namlen);
  226                         dirent_terminate(&dstdp);
  227                         if (dstdp.d_reclen > uio->uio_resid) {
  228                                 if (uio->uio_resid == startresid)
  229                                         error = EINVAL;
  230                                 else
  231                                         error = EJUSTRETURN;
  232                                 break;
  233                         }
  234                         /* Advance dp. */
  235                         error = uiomove((caddr_t)&dstdp, dstdp.d_reclen, uio);
  236                         if (error)
  237                                 break;
  238                         if (cookies != NULL) {
  239                                 KASSERT(ncookies > 0,
  240                                     ("ext2_readdir: cookies buffer too small"));
  241                                 *cookies = offset + dp->e2d_reclen;
  242                                 cookies++;
  243                                 ncookies--;
  244                         }
  245 nextentry:
  246                         offset += dp->e2d_reclen;
  247                         dp = (struct ext2fs_direct_2 *)((caddr_t)dp +
  248                             dp->e2d_reclen);
  249                 }
  250                 bqrelse(bp);
  251                 uio->uio_offset = offset;
  252         }
  253         /* We need to correct uio_offset. */
  254         uio->uio_offset = offset;
  255         if (error == EJUSTRETURN)
  256                 error = 0;
  257         if (ap->a_ncookies != NULL) {
  258                 if (error == 0) {
  259                         ap->a_ncookies -= ncookies;
  260                 } else {
  261                         free(*ap->a_cookies, M_TEMP);
  262                         *ap->a_ncookies = 0;
  263                         *ap->a_cookies = NULL;
  264                 }
  265         }
  266         if (error == 0 && ap->a_eofflag)
  267                 *ap->a_eofflag = ip->i_size <= uio->uio_offset;
  268         return (error);
  269 }
  270 
  271 /*
  272  * Convert a component of a pathname into a pointer to a locked inode.
  273  * This is a very central and rather complicated routine.
  274  * If the file system is not maintained in a strict tree hierarchy,
  275  * this can result in a deadlock situation (see comments in code below).
  276  *
  277  * The cnp->cn_nameiop argument is LOOKUP, CREATE, RENAME, or DELETE depending
  278  * on whether the name is to be looked up, created, renamed, or deleted.
  279  * When CREATE, RENAME, or DELETE is specified, information usable in
  280  * creating, renaming, or deleting a directory entry may be calculated.
  281  * If flag has LOCKPARENT or'ed into it and the target of the pathname
  282  * exists, lookup returns both the target and its parent directory locked.
  283  * When creating or renaming and LOCKPARENT is specified, the target may
  284  * not be ".".  When deleting and LOCKPARENT is specified, the target may
  285  * be "."., but the caller must check to ensure it does an vrele and vput
  286  * instead of two vputs.
  287  *
  288  * Overall outline of ext2_lookup:
  289  *
  290  *      search for name in directory, to found or notfound
  291  * notfound:
  292  *      if creating, return locked directory, leaving info on available slots
  293  *      else return error
  294  * found:
  295  *      if at end of path and deleting, return information to allow delete
  296  *      if at end of path and rewriting (RENAME and LOCKPARENT), lock target
  297  *        inode and return info to allow rewrite
  298  *      if not at end, add name to cache; if at end and neither creating
  299  *        nor deleting, add name to cache
  300  */
  301 int
  302 ext2_lookup(struct vop_cachedlookup_args *ap)
  303 {
  304 
  305         return (ext2_lookup_ino(ap->a_dvp, ap->a_vpp, ap->a_cnp, NULL));
  306 }
  307 
  308 static int
  309 ext2_lookup_ino(struct vnode *vdp, struct vnode **vpp, struct componentname *cnp,
  310     ino_t *dd_ino)
  311 {
  312         struct inode *dp;               /* inode for directory being searched */
  313         struct buf *bp;                 /* a buffer of directory entries */
  314         struct ext2fs_direct_2 *ep;     /* the current directory entry */
  315         int entryoffsetinblock;         /* offset of ep in bp's buffer */
  316         struct ext2fs_searchslot ss;
  317         doff_t i_diroff;                /* cached i_diroff value */
  318         doff_t i_offset;                /* cached i_offset value */
  319         int numdirpasses;               /* strategy for directory search */
  320         doff_t endsearch;               /* offset to end directory search */
  321         doff_t prevoff;                 /* prev entry dp->i_offset */
  322         struct vnode *pdp;              /* saved dp during symlink work */
  323         struct vnode *tdp;              /* returned by VFS_VGET */
  324         doff_t enduseful;               /* pointer past last used dir slot */
  325         u_long bmask;                   /* block offset mask */
  326         int error;
  327         struct ucred *cred = cnp->cn_cred;
  328         int flags = cnp->cn_flags;
  329         int nameiop = cnp->cn_nameiop;
  330         ino_t ino, ino1;
  331         int ltype;
  332         int entry_found = 0;
  333 
  334         int DIRBLKSIZ = VTOI(vdp)->i_e2fs->e2fs_bsize;
  335 
  336         if (vpp != NULL)
  337                 *vpp = NULL;
  338 
  339         dp = VTOI(vdp);
  340         bmask = VFSTOEXT2(vdp->v_mount)->um_mountp->mnt_stat.f_iosize - 1;
  341 restart:
  342         bp = NULL;
  343         ss.slotoffset = -1;
  344 
  345         /*
  346          * We now have a segment name to search for, and a directory to search.
  347          *
  348          * Suppress search for slots unless creating
  349          * file and at end of pathname, in which case
  350          * we watch for a place to put the new file in
  351          * case it doesn't already exist.
  352          */
  353         i_diroff = dp->i_diroff;
  354         ss.slotstatus = FOUND;
  355         ss.slotfreespace = ss.slotsize = ss.slotneeded = 0;
  356         if ((nameiop == CREATE || nameiop == RENAME) &&
  357             (flags & ISLASTCN)) {
  358                 ss.slotstatus = NONE;
  359                 ss.slotneeded = EXT2_DIR_REC_LEN(cnp->cn_namelen);
  360                 /*
  361                  * was ss.slotneeded = (sizeof(struct direct) - MAXNAMLEN +
  362                  * cnp->cn_namelen + 3) &~ 3;
  363                  */
  364         }
  365         /*
  366          * Try to lookup dir entry using htree directory index.
  367          *
  368          * If we got an error or we want to find '.' or '..' entry,
  369          * we will fall back to linear search.
  370          */
  371         if (!ext2_is_dot_entry(cnp) && ext2_htree_has_idx(dp)) {
  372                 numdirpasses = 1;
  373                 entryoffsetinblock = 0;
  374                 switch (ext2_htree_lookup(dp, cnp->cn_nameptr, cnp->cn_namelen,
  375                     &bp, &entryoffsetinblock, &i_offset, &prevoff,
  376                     &enduseful, &ss)) {
  377                 case 0:
  378                         ep = (struct ext2fs_direct_2 *)((char *)bp->b_data +
  379                             (i_offset & bmask));
  380                         goto foundentry;
  381                 case ENOENT:
  382                         i_offset = roundup2(dp->i_size, DIRBLKSIZ);
  383                         goto notfound;
  384                 default:
  385                         /*
  386                          * Something failed; just fallback to do a linear
  387                          * search.
  388                          */
  389                         break;
  390                 }
  391         }
  392 
  393         /*
  394          * If there is cached information on a previous search of
  395          * this directory, pick up where we last left off.
  396          * We cache only lookups as these are the most common
  397          * and have the greatest payoff. Caching CREATE has little
  398          * benefit as it usually must search the entire directory
  399          * to determine that the entry does not exist. Caching the
  400          * location of the last DELETE or RENAME has not reduced
  401          * profiling time and hence has been removed in the interest
  402          * of simplicity.
  403          */
  404         if (nameiop != LOOKUP || i_diroff == 0 ||
  405             i_diroff > dp->i_size) {
  406                 entryoffsetinblock = 0;
  407                 i_offset = 0;
  408                 numdirpasses = 1;
  409         } else {
  410                 i_offset = i_diroff;
  411                 if ((entryoffsetinblock = i_offset & bmask) &&
  412                     (error = ext2_blkatoff(vdp, (off_t)i_offset, NULL,
  413                     &bp)))
  414                         return (error);
  415                 numdirpasses = 2;
  416                 nchstats.ncs_2passes++;
  417         }
  418         prevoff = i_offset;
  419         endsearch = roundup2(dp->i_size, DIRBLKSIZ);
  420         enduseful = 0;
  421 
  422 searchloop:
  423         while (i_offset < endsearch) {
  424                 /*
  425                  * If necessary, get the next directory block.
  426                  */
  427                 if (bp != NULL)
  428                         brelse(bp);
  429                 error = ext2_blkatoff(vdp, (off_t)i_offset, NULL, &bp);
  430                 if (error != 0)
  431                         return (error);
  432 
  433                 entryoffsetinblock = 0;
  434                 if (ss.slotstatus == NONE) {
  435                         ss.slotoffset = -1;
  436                         ss.slotfreespace = 0;
  437                 }
  438 
  439                 error = ext2_search_dirblock(dp, bp->b_data, &entry_found,
  440                     cnp->cn_nameptr, cnp->cn_namelen,
  441                     &entryoffsetinblock, &i_offset, &prevoff,
  442                     &enduseful, &ss);
  443                 if (error != 0) {
  444                         brelse(bp);
  445                         return (error);
  446                 }
  447                 if (entry_found) {
  448                         ep = (struct ext2fs_direct_2 *)((char *)bp->b_data +
  449                             (entryoffsetinblock & bmask));
  450 foundentry:
  451                         ino = ep->e2d_ino;
  452                         goto found;
  453                 }
  454         }
  455 notfound:
  456         /*
  457          * If we started in the middle of the directory and failed
  458          * to find our target, we must check the beginning as well.
  459          */
  460         if (numdirpasses == 2) {
  461                 numdirpasses--;
  462                 i_offset = 0;
  463                 endsearch = i_diroff;
  464                 goto searchloop;
  465         }
  466         if (bp != NULL)
  467                 brelse(bp);
  468         /*
  469          * If creating, and at end of pathname and current
  470          * directory has not been removed, then can consider
  471          * allowing file to be created.
  472          */
  473         if ((nameiop == CREATE || nameiop == RENAME) &&
  474             (flags & ISLASTCN) && dp->i_nlink != 0) {
  475                 /*
  476                  * Access for write is interpreted as allowing
  477                  * creation of files in the directory.
  478                  */
  479                 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0)
  480                         return (error);
  481                 /*
  482                  * Return an indication of where the new directory
  483                  * entry should be put.  If we didn't find a slot,
  484                  * then set dp->i_count to 0 indicating
  485                  * that the new slot belongs at the end of the
  486                  * directory. If we found a slot, then the new entry
  487                  * can be put in the range from dp->i_offset to
  488                  * dp->i_offset + dp->i_count.
  489                  */
  490                 if (ss.slotstatus == NONE) {
  491                         dp->i_offset = roundup2(dp->i_size, DIRBLKSIZ);
  492                         dp->i_count = 0;
  493                         enduseful = dp->i_offset;
  494                 } else {
  495                         dp->i_offset = ss.slotoffset;
  496                         dp->i_count = ss.slotsize;
  497                         if (enduseful < ss.slotoffset + ss.slotsize)
  498                                 enduseful = ss.slotoffset + ss.slotsize;
  499                 }
  500                 dp->i_endoff = roundup2(enduseful, DIRBLKSIZ);
  501                 /*
  502                  * We return with the directory locked, so that
  503                  * the parameters we set up above will still be
  504                  * valid if we actually decide to do a direnter().
  505                  * We return ni_vp == NULL to indicate that the entry
  506                  * does not currently exist; we leave a pointer to
  507                  * the (locked) directory inode in ndp->ni_dvp.
  508                  * The pathname buffer is saved so that the name
  509                  * can be obtained later.
  510                  *
  511                  * NB - if the directory is unlocked, then this
  512                  * information cannot be used.
  513                  */
  514                 cnp->cn_flags |= SAVENAME;
  515                 return (EJUSTRETURN);
  516         }
  517         /*
  518          * Insert name into cache (as non-existent) if appropriate.
  519          */
  520         if ((cnp->cn_flags & MAKEENTRY) != 0)
  521                 cache_enter(vdp, NULL, cnp);
  522         return (ENOENT);
  523 
  524 found:
  525         if (dd_ino != NULL)
  526                 *dd_ino = ino;
  527         if (numdirpasses == 2)
  528                 nchstats.ncs_pass2++;
  529         /*
  530          * Check that directory length properly reflects presence
  531          * of this entry.
  532          */
  533         if (entryoffsetinblock + EXT2_DIR_REC_LEN(ep->e2d_namlen)
  534             > dp->i_size) {
  535                 ext2_dirbad(dp, i_offset, "i_size too small");
  536                 dp->i_size = entryoffsetinblock + EXT2_DIR_REC_LEN(ep->e2d_namlen);
  537                 dp->i_flag |= IN_CHANGE | IN_UPDATE;
  538         }
  539         brelse(bp);
  540 
  541         /*
  542          * Found component in pathname.
  543          * If the final component of path name, save information
  544          * in the cache as to where the entry was found.
  545          */
  546         if ((flags & ISLASTCN) && nameiop == LOOKUP)
  547                 dp->i_diroff = rounddown2(i_offset, DIRBLKSIZ);
  548         /*
  549          * If deleting, and at end of pathname, return
  550          * parameters which can be used to remove file.
  551          */
  552         if (nameiop == DELETE && (flags & ISLASTCN)) {
  553                 if (flags & LOCKPARENT)
  554                         ASSERT_VOP_ELOCKED(vdp, __FUNCTION__);
  555                 /*
  556                  * Write access to directory required to delete files.
  557                  */
  558                 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0)
  559                         return (error);
  560                 /*
  561                  * Return pointer to current entry in dp->i_offset,
  562                  * and distance past previous entry (if there
  563                  * is a previous entry in this block) in dp->i_count.
  564                  * Save directory inode pointer in ndp->ni_dvp for dirremove().
  565                  *
  566                  * Technically we shouldn't be setting these in the
  567                  * WANTPARENT case (first lookup in rename()), but any
  568                  * lookups that will result in directory changes will
  569                  * overwrite these.
  570                  */
  571                 dp->i_offset = i_offset;
  572                 if ((dp->i_offset & (DIRBLKSIZ - 1)) == 0)
  573                         dp->i_count = 0;
  574                 else
  575                         dp->i_count = dp->i_offset - prevoff;
  576                 if (dd_ino != NULL)
  577                         return (0);
  578                 if (dp->i_number == ino) {
  579                         VREF(vdp);
  580                         *vpp = vdp;
  581                         return (0);
  582                 }
  583                 if ((error = VFS_VGET(vdp->v_mount, ino, LK_EXCLUSIVE,
  584                     &tdp)) != 0)
  585                         return (error);
  586                 /*
  587                  * If directory is "sticky", then user must own
  588                  * the directory, or the file in it, else she
  589                  * may not delete it (unless she's root). This
  590                  * implements append-only directories.
  591                  */
  592                 if ((dp->i_mode & ISVTX) &&
  593                     cred->cr_uid != 0 &&
  594                     cred->cr_uid != dp->i_uid &&
  595                     VTOI(tdp)->i_uid != cred->cr_uid) {
  596                         vput(tdp);
  597                         return (EPERM);
  598                 }
  599                 *vpp = tdp;
  600                 return (0);
  601         }
  602 
  603         /*
  604          * If rewriting (RENAME), return the inode and the
  605          * information required to rewrite the present directory
  606          * Must get inode of directory entry to verify it's a
  607          * regular file, or empty directory.
  608          */
  609         if (nameiop == RENAME && (flags & ISLASTCN)) {
  610                 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0)
  611                         return (error);
  612                 /*
  613                  * Careful about locking second inode.
  614                  * This can only occur if the target is ".".
  615                  */
  616                 dp->i_offset = i_offset;
  617                 if (dp->i_number == ino)
  618                         return (EISDIR);
  619                 if (dd_ino != NULL)
  620                         return (0);
  621                 if ((error = VFS_VGET(vdp->v_mount, ino, LK_EXCLUSIVE,
  622                     &tdp)) != 0)
  623                         return (error);
  624                 *vpp = tdp;
  625                 cnp->cn_flags |= SAVENAME;
  626                 return (0);
  627         }
  628         if (dd_ino != NULL)
  629                 return (0);
  630 
  631         /*
  632          * Step through the translation in the name.  We do not `vput' the
  633          * directory because we may need it again if a symbolic link
  634          * is relative to the current directory.  Instead we save it
  635          * unlocked as "pdp".  We must get the target inode before unlocking
  636          * the directory to insure that the inode will not be removed
  637          * before we get it.  We prevent deadlock by always fetching
  638          * inodes from the root, moving down the directory tree. Thus
  639          * when following backward pointers ".." we must unlock the
  640          * parent directory before getting the requested directory.
  641          * There is a potential race condition here if both the current
  642          * and parent directories are removed before the VFS_VGET for the
  643          * inode associated with ".." returns.  We hope that this occurs
  644          * infrequently since we cannot avoid this race condition without
  645          * implementing a sophisticated deadlock detection algorithm.
  646          * Note also that this simple deadlock detection scheme will not
  647          * work if the file system has any hard links other than ".."
  648          * that point backwards in the directory structure.
  649          */
  650         pdp = vdp;
  651         if (flags & ISDOTDOT) {
  652                 error = vn_vget_ino(pdp, ino, cnp->cn_lkflags, &tdp);
  653                 if (pdp->v_iflag & VI_DOOMED) {
  654                         if (error == 0)
  655                                 vput(tdp);
  656                         error = ENOENT;
  657                 }
  658                 if (error)
  659                         return (error);
  660                 /*
  661                  * Recheck that ".." entry in the vdp directory points
  662                  * to the inode we looked up before vdp lock was
  663                  * dropped.
  664                  */
  665                 error = ext2_lookup_ino(pdp, NULL, cnp, &ino1);
  666                 if (error) {
  667                         vput(tdp);
  668                         return (error);
  669                 }
  670                 if (ino1 != ino) {
  671                         vput(tdp);
  672                         goto restart;
  673                 }
  674                 *vpp = tdp;
  675         } else if (dp->i_number == ino) {
  676                 VREF(vdp);      /* we want ourself, ie "." */
  677                 /*
  678                  * When we lookup "." we still can be asked to lock it
  679                  * differently.
  680                  */
  681                 ltype = cnp->cn_lkflags & LK_TYPE_MASK;
  682                 if (ltype != VOP_ISLOCKED(vdp)) {
  683                         if (ltype == LK_EXCLUSIVE)
  684                                 vn_lock(vdp, LK_UPGRADE | LK_RETRY);
  685                         else    /* if (ltype == LK_SHARED) */
  686                                 vn_lock(vdp, LK_DOWNGRADE | LK_RETRY);
  687                 }
  688                 *vpp = vdp;
  689         } else {
  690                 if ((error = VFS_VGET(vdp->v_mount, ino, cnp->cn_lkflags,
  691                     &tdp)) != 0)
  692                         return (error);
  693                 *vpp = tdp;
  694         }
  695 
  696         /*
  697          * Insert name into cache if appropriate.
  698          */
  699         if (cnp->cn_flags & MAKEENTRY)
  700                 cache_enter(vdp, *vpp, cnp);
  701         return (0);
  702 }
  703 
  704 int
  705 ext2_search_dirblock(struct inode *ip, void *data, int *foundp,
  706     const char *name, int namelen, int *entryoffsetinblockp,
  707     doff_t *offp, doff_t *prevoffp, doff_t *endusefulp,
  708     struct ext2fs_searchslot *ssp)
  709 {
  710         struct vnode *vdp;
  711         struct ext2fs_direct_2 *ep, *top;
  712         uint32_t bsize = ip->i_e2fs->e2fs_bsize;
  713         int offset = *entryoffsetinblockp;
  714         int namlen;
  715 
  716         vdp = ITOV(ip);
  717 
  718         ep = (struct ext2fs_direct_2 *)((char *)data + offset);
  719         top = (struct ext2fs_direct_2 *)((char *)data + bsize);
  720         while (ep < top) {
  721                 /*
  722                  * Full validation checks are slow, so we only check
  723                  * enough to insure forward progress through the
  724                  * directory. Complete checks can be run by setting
  725                  * "vfs.e2fs.dirchk" to be true.
  726                  */
  727                 if (ep->e2d_reclen == 0 ||
  728                     (dirchk && ext2_dirbadentry(vdp, ep, offset))) {
  729                         int i;
  730 
  731                         ext2_dirbad(ip, *offp, "mangled entry");
  732                         i = bsize - (offset & (bsize - 1));
  733                         *offp += i;
  734                         offset += i;
  735                         continue;
  736                 }
  737 
  738                 /*
  739                  * If an appropriate sized slot has not yet been found,
  740                  * check to see if one is available. Also accumulate space
  741                  * in the current block so that we can determine if
  742                  * compaction is viable.
  743                  */
  744                 if (ssp->slotstatus != FOUND) {
  745                         int size = ep->e2d_reclen;
  746 
  747                         if (ep->e2d_ino != 0)
  748                                 size -= EXT2_DIR_REC_LEN(ep->e2d_namlen);
  749                         else if (ext2_is_dirent_tail(ip, ep))
  750                                 size -= sizeof(struct ext2fs_direct_tail);
  751                         if (size > 0) {
  752                                 if (size >= ssp->slotneeded) {
  753                                         ssp->slotstatus = FOUND;
  754                                         ssp->slotoffset = *offp;
  755                                         ssp->slotsize = ep->e2d_reclen;
  756                                 } else if (ssp->slotstatus == NONE) {
  757                                         ssp->slotfreespace += size;
  758                                         if (ssp->slotoffset == -1)
  759                                                 ssp->slotoffset = *offp;
  760                                         if (ssp->slotfreespace >= ssp->slotneeded) {
  761                                                 ssp->slotstatus = COMPACT;
  762                                                 ssp->slotsize = *offp +
  763                                                     ep->e2d_reclen -
  764                                                     ssp->slotoffset;
  765                                         }
  766                                 }
  767                         }
  768                 }
  769                 /*
  770                  * Check for a name match.
  771                  */
  772                 if (ep->e2d_ino) {
  773                         namlen = ep->e2d_namlen;
  774                         if (namlen == namelen &&
  775                             !bcmp(name, ep->e2d_name, (unsigned)namlen)) {
  776                                 /*
  777                                  * Save directory entry's inode number and
  778                                  * reclen in ndp->ni_ufs area, and release
  779                                  * directory buffer.
  780                                  */
  781                                 *foundp = 1;
  782                                 return (0);
  783                         }
  784                 }
  785                 *prevoffp = *offp;
  786                 *offp += ep->e2d_reclen;
  787                 offset += ep->e2d_reclen;
  788                 *entryoffsetinblockp = offset;
  789                 if (ep->e2d_ino)
  790                         *endusefulp = *offp;
  791                 /*
  792                  * Get pointer to the next entry.
  793                  */
  794                 ep = (struct ext2fs_direct_2 *)((char *)data + offset);
  795         }
  796 
  797         return (0);
  798 }
  799 
  800 void
  801 ext2_dirbad(struct inode *ip, doff_t offset, char *how)
  802 {
  803         struct mount *mp;
  804 
  805         mp = ITOV(ip)->v_mount;
  806         if ((mp->mnt_flag & MNT_RDONLY) == 0)
  807                 panic("ext2_dirbad: %s: bad dir ino %ju at offset %ld: %s\n",
  808                     mp->mnt_stat.f_mntonname, (uintmax_t)ip->i_number,
  809                     (long)offset, how);
  810         else
  811                 (void)printf("%s: bad dir ino %ju at offset %ld: %s\n",
  812                     mp->mnt_stat.f_mntonname, (uintmax_t)ip->i_number,
  813                     (long)offset, how);
  814 
  815 }
  816 
  817 /*
  818  * Do consistency checking on a directory entry:
  819  *      record length must be multiple of 4
  820  *      entry must fit in rest of its DIRBLKSIZ block
  821  *      record must be large enough to contain entry
  822  *      name is not longer than MAXNAMLEN
  823  *      name must be as long as advertised, and null terminated
  824  */
  825 /*
  826  *      changed so that it confirms to ext2_check_dir_entry
  827  */
  828 static int
  829 ext2_dirbadentry(struct vnode *dp, struct ext2fs_direct_2 *de,
  830     int entryoffsetinblock)
  831 {
  832         int DIRBLKSIZ = VTOI(dp)->i_e2fs->e2fs_bsize;
  833 
  834         char *error_msg = NULL;
  835 
  836         if (de->e2d_reclen < EXT2_DIR_REC_LEN(1))
  837                 error_msg = "rec_len is smaller than minimal";
  838         else if (de->e2d_reclen % 4 != 0)
  839                 error_msg = "rec_len % 4 != 0";
  840         else if (de->e2d_reclen < EXT2_DIR_REC_LEN(de->e2d_namlen))
  841                 error_msg = "reclen is too small for name_len";
  842         else if (entryoffsetinblock + de->e2d_reclen > DIRBLKSIZ)
  843                 error_msg = "directory entry across blocks";
  844         /* else LATER
  845              if (de->inode > dir->i_sb->u.ext2_sb.s_es->s_inodes_count)
  846                 error_msg = "inode out of bounds";
  847         */
  848 
  849         if (error_msg != NULL) {
  850                 printf("bad directory entry: %s\n", error_msg);
  851                 printf("offset=%d, inode=%lu, rec_len=%u, name_len=%u\n",
  852                         entryoffsetinblock, (unsigned long)de->e2d_ino,
  853                         de->e2d_reclen, de->e2d_namlen);
  854         }
  855         return error_msg == NULL ? 0 : 1;
  856 }
  857 
  858 /*
  859  * Insert an entry into the fresh directory block.
  860  * Initialize entry tail if the metadata_csum feature is turned on.
  861  */
  862 static int
  863 ext2_add_first_entry(struct vnode *dvp, struct ext2fs_direct_2 *entry,
  864     struct componentname *cnp)
  865 {
  866         struct inode *dp;
  867         struct iovec aiov;
  868         struct uio auio;
  869         char* buf = NULL;
  870         int dirblksize, error;
  871 
  872         dp = VTOI(dvp);
  873         dirblksize = dp->i_e2fs->e2fs_bsize;
  874 
  875         if (dp->i_offset & (dirblksize - 1))
  876                 panic("ext2_add_first_entry: bad directory offset");
  877 
  878         if (EXT2_HAS_RO_COMPAT_FEATURE(dp->i_e2fs,
  879             EXT2F_ROCOMPAT_METADATA_CKSUM)) {
  880                 entry->e2d_reclen = dirblksize - sizeof(struct ext2fs_direct_tail);
  881                 buf = malloc(dirblksize, M_TEMP, M_WAITOK);
  882                 if (!buf) {
  883                         error = ENOMEM;
  884                         goto out;
  885                 }
  886                 memcpy(buf, entry, EXT2_DIR_REC_LEN(entry->e2d_namlen));
  887                 ext2_init_dirent_tail(EXT2_DIRENT_TAIL(buf, dirblksize));
  888                 ext2_dirent_csum_set(dp, (struct ext2fs_direct_2 *)buf);
  889 
  890                 auio.uio_offset = dp->i_offset;
  891                 auio.uio_resid = dirblksize;
  892                 aiov.iov_len = auio.uio_resid;
  893                 aiov.iov_base = (caddr_t)buf;
  894         } else {
  895                 entry->e2d_reclen = dirblksize;
  896                 auio.uio_offset = dp->i_offset;
  897                 auio.uio_resid = EXT2_DIR_REC_LEN(entry->e2d_namlen);
  898                 aiov.iov_len = auio.uio_resid;
  899                 aiov.iov_base = (caddr_t)entry;
  900         }
  901 
  902         auio.uio_iov = &aiov;
  903         auio.uio_iovcnt = 1;
  904         auio.uio_rw = UIO_WRITE;
  905         auio.uio_segflg = UIO_SYSSPACE;
  906         auio.uio_td = (struct thread *)0;
  907         error = VOP_WRITE(dvp, &auio, IO_SYNC, cnp->cn_cred);
  908         if (error)
  909                 goto out;
  910 
  911         dp->i_size = roundup2(dp->i_size, dirblksize);
  912         dp->i_flag |= IN_CHANGE;
  913 
  914 out:
  915         free(buf, M_TEMP);
  916         return (error);
  917 
  918 }
  919 
  920 /*
  921  * Write a directory entry after a call to namei, using the parameters
  922  * that it left in nameidata.  The argument ip is the inode which the new
  923  * directory entry will refer to.  Dvp is a pointer to the directory to
  924  * be written, which was left locked by namei. Remaining parameters
  925  * (dp->i_offset, dp->i_count) indicate how the space for the new
  926  * entry is to be obtained.
  927  */
  928 int
  929 ext2_direnter(struct inode *ip, struct vnode *dvp, struct componentname *cnp)
  930 {
  931         struct inode *dp;
  932         struct ext2fs_direct_2 newdir;
  933         int DIRBLKSIZ = ip->i_e2fs->e2fs_bsize;
  934         int error;
  935 
  936 
  937 #ifdef INVARIANTS
  938         if ((cnp->cn_flags & SAVENAME) == 0)
  939                 panic("ext2_direnter: missing name");
  940 #endif
  941         dp = VTOI(dvp);
  942         newdir.e2d_ino = ip->i_number;
  943         newdir.e2d_namlen = cnp->cn_namelen;
  944         if (EXT2_HAS_INCOMPAT_FEATURE(ip->i_e2fs,
  945             EXT2F_INCOMPAT_FTYPE))
  946                 newdir.e2d_type = DTTOFT(IFTODT(ip->i_mode));
  947         else
  948                 newdir.e2d_type = EXT2_FT_UNKNOWN;
  949         bcopy(cnp->cn_nameptr, newdir.e2d_name, (unsigned)cnp->cn_namelen + 1);
  950 
  951         if (ext2_htree_has_idx(dp)) {
  952                 error = ext2_htree_add_entry(dvp, &newdir, cnp);
  953                 if (error) {
  954                         dp->i_flag &= ~IN_E3INDEX;
  955                         dp->i_flag |= IN_CHANGE | IN_UPDATE;
  956                 }
  957                 return (error);
  958         }
  959 
  960         if (EXT2_HAS_COMPAT_FEATURE(ip->i_e2fs, EXT2F_COMPAT_DIRHASHINDEX) &&
  961             !ext2_htree_has_idx(dp)) {
  962                 if ((dp->i_size / DIRBLKSIZ) == 1 &&
  963                     dp->i_offset == DIRBLKSIZ) {
  964                         /*
  965                          * Making indexed directory when one block is not
  966                          * enough to save all entries.
  967                          */
  968                         return ext2_htree_create_index(dvp, cnp, &newdir);
  969                 }
  970         }
  971 
  972         /*
  973          * If dp->i_count is 0, then namei could find no
  974          * space in the directory. Here, dp->i_offset will
  975          * be on a directory block boundary and we will write the
  976          * new entry into a fresh block.
  977          */
  978         if (dp->i_count == 0)
  979                 return ext2_add_first_entry(dvp, &newdir, cnp);
  980 
  981         error = ext2_add_entry(dvp, &newdir);
  982         if (!error && dp->i_endoff && dp->i_endoff < dp->i_size)
  983                 error = ext2_truncate(dvp, (off_t)dp->i_endoff, IO_SYNC,
  984                     cnp->cn_cred, cnp->cn_thread);
  985         return (error);
  986 }
  987 
  988 /*
  989  * Insert an entry into the directory block.
  990  * Compact the contents.
  991  */
  992 int
  993 ext2_add_entry(struct vnode *dvp, struct ext2fs_direct_2 *entry)
  994 {
  995         struct ext2fs_direct_2 *ep, *nep;
  996         struct inode *dp;
  997         struct buf *bp;
  998         u_int dsize;
  999         int error, loc, newentrysize, spacefree;
 1000         char *dirbuf;
 1001 
 1002         dp = VTOI(dvp);
 1003 
 1004         /*
 1005          * If dp->i_count is non-zero, then namei found space
 1006          * for the new entry in the range dp->i_offset to
 1007          * dp->i_offset + dp->i_count in the directory.
 1008          * To use this space, we may have to compact the entries located
 1009          * there, by copying them together towards the beginning of the
 1010          * block, leaving the free space in one usable chunk at the end.
 1011          */
 1012 
 1013         /*
 1014          * Increase size of directory if entry eats into new space.
 1015          * This should never push the size past a new multiple of
 1016          * DIRBLKSIZE.
 1017          *
 1018          * N.B. - THIS IS AN ARTIFACT OF 4.2 AND SHOULD NEVER HAPPEN.
 1019          */
 1020         if (dp->i_offset + dp->i_count > dp->i_size)
 1021                 dp->i_size = dp->i_offset + dp->i_count;
 1022         /*
 1023          * Get the block containing the space for the new directory entry.
 1024          */
 1025         if ((error = ext2_blkatoff(dvp, (off_t)dp->i_offset, &dirbuf,
 1026             &bp)) != 0)
 1027                 return (error);
 1028         /*
 1029          * Find space for the new entry. In the simple case, the entry at
 1030          * offset base will have the space. If it does not, then namei
 1031          * arranged that compacting the region dp->i_offset to
 1032          * dp->i_offset + dp->i_count would yield the
 1033          * space.
 1034          */
 1035         newentrysize = EXT2_DIR_REC_LEN(entry->e2d_namlen);
 1036         ep = (struct ext2fs_direct_2 *)dirbuf;
 1037         dsize = EXT2_DIR_REC_LEN(ep->e2d_namlen);
 1038         spacefree = ep->e2d_reclen - dsize;
 1039         for (loc = ep->e2d_reclen; loc < dp->i_count; ) {
 1040                 nep = (struct ext2fs_direct_2 *)(dirbuf + loc);
 1041                 if (ep->e2d_ino) {
 1042                         /* trim the existing slot */
 1043                         ep->e2d_reclen = dsize;
 1044                         ep = (struct ext2fs_direct_2 *)((char *)ep + dsize);
 1045                 } else {
 1046                         /* overwrite; nothing there; header is ours */
 1047                         spacefree += dsize;
 1048                 }
 1049                 dsize = EXT2_DIR_REC_LEN(nep->e2d_namlen);
 1050                 spacefree += nep->e2d_reclen - dsize;
 1051                 loc += nep->e2d_reclen;
 1052                 bcopy((caddr_t)nep, (caddr_t)ep, dsize);
 1053         }
 1054         /*
 1055          * Update the pointer fields in the previous entry (if any),
 1056          * copy in the new entry, and write out the block.
 1057          */
 1058         if (ep->e2d_ino == 0) {
 1059                 if (spacefree + dsize < newentrysize)
 1060                         panic("ext2_direnter: compact1");
 1061                 entry->e2d_reclen = spacefree + dsize;
 1062         } else {
 1063                 if (spacefree < newentrysize)
 1064                         panic("ext2_direnter: compact2");
 1065                 entry->e2d_reclen = spacefree;
 1066                 ep->e2d_reclen = dsize;
 1067                 ep = (struct ext2fs_direct_2 *)((char *)ep + dsize);
 1068         }
 1069         bcopy((caddr_t)entry, (caddr_t)ep, (u_int)newentrysize);
 1070         ext2_dirent_csum_set(dp, (struct ext2fs_direct_2 *)bp->b_data);
 1071         if (DOINGASYNC(dvp)) {
 1072                 bdwrite(bp);
 1073                 error = 0;
 1074         } else {
 1075                 error = bwrite(bp);
 1076         }
 1077         dp->i_flag |= IN_CHANGE | IN_UPDATE;
 1078         return (error);
 1079 }
 1080 
 1081 /*
 1082  * Remove a directory entry after a call to namei, using
 1083  * the parameters which it left in nameidata. The entry
 1084  * dp->i_offset contains the offset into the directory of the
 1085  * entry to be eliminated.  The dp->i_count field contains the
 1086  * size of the previous record in the directory.  If this
 1087  * is 0, the first entry is being deleted, so we need only
 1088  * zero the inode number to mark the entry as free.  If the
 1089  * entry is not the first in the directory, we must reclaim
 1090  * the space of the now empty record by adding the record size
 1091  * to the size of the previous entry.
 1092  */
 1093 int
 1094 ext2_dirremove(struct vnode *dvp, struct componentname *cnp)
 1095 {
 1096         struct inode *dp;
 1097         struct ext2fs_direct_2 *ep, *rep;
 1098         struct buf *bp;
 1099         int error;
 1100 
 1101         dp = VTOI(dvp);
 1102         if (dp->i_count == 0) {
 1103                 /*
 1104                  * First entry in block: set d_ino to zero.
 1105                  */
 1106                 if ((error =
 1107                     ext2_blkatoff(dvp, (off_t)dp->i_offset, (char **)&ep,
 1108                     &bp)) != 0)
 1109                         return (error);
 1110                 ep->e2d_ino = 0;
 1111                 ext2_dirent_csum_set(dp, (struct ext2fs_direct_2 *)bp->b_data);
 1112                 error = bwrite(bp);
 1113                 dp->i_flag |= IN_CHANGE | IN_UPDATE;
 1114                 return (error);
 1115         }
 1116         /*
 1117          * Collapse new free space into previous entry.
 1118          */
 1119         if ((error = ext2_blkatoff(dvp, (off_t)(dp->i_offset - dp->i_count),
 1120             (char **)&ep, &bp)) != 0)
 1121                 return (error);
 1122 
 1123         /* Set 'rep' to the entry being removed. */
 1124         if (dp->i_count == 0)
 1125                 rep = ep;
 1126         else
 1127                 rep = (struct ext2fs_direct_2 *)((char *)ep + ep->e2d_reclen);
 1128         ep->e2d_reclen += rep->e2d_reclen;
 1129         ext2_dirent_csum_set(dp, (struct ext2fs_direct_2 *)bp->b_data);
 1130         if (DOINGASYNC(dvp) && dp->i_count != 0)
 1131                 bdwrite(bp);
 1132         else
 1133                 error = bwrite(bp);
 1134         dp->i_flag |= IN_CHANGE | IN_UPDATE;
 1135         return (error);
 1136 }
 1137 
 1138 /*
 1139  * Rewrite an existing directory entry to point at the inode
 1140  * supplied.  The parameters describing the directory entry are
 1141  * set up by a call to namei.
 1142  */
 1143 int
 1144 ext2_dirrewrite(struct inode *dp, struct inode *ip, struct componentname *cnp)
 1145 {
 1146         struct buf *bp;
 1147         struct ext2fs_direct_2 *ep;
 1148         struct vnode *vdp = ITOV(dp);
 1149         int error;
 1150 
 1151         if ((error = ext2_blkatoff(vdp, (off_t)dp->i_offset, (char **)&ep,
 1152             &bp)) != 0)
 1153                 return (error);
 1154         ep->e2d_ino = ip->i_number;
 1155         if (EXT2_HAS_INCOMPAT_FEATURE(ip->i_e2fs,
 1156             EXT2F_INCOMPAT_FTYPE))
 1157                 ep->e2d_type = DTTOFT(IFTODT(ip->i_mode));
 1158         else
 1159                 ep->e2d_type = EXT2_FT_UNKNOWN;
 1160         ext2_dirent_csum_set(dp, (struct ext2fs_direct_2 *)bp->b_data);
 1161         error = bwrite(bp);
 1162         dp->i_flag |= IN_CHANGE | IN_UPDATE;
 1163         return (error);
 1164 }
 1165 
 1166 /*
 1167  * Check if a directory is empty or not.
 1168  * Inode supplied must be locked.
 1169  *
 1170  * Using a struct dirtemplate here is not precisely
 1171  * what we want, but better than using a struct direct.
 1172  *
 1173  * NB: does not handle corrupted directories.
 1174  */
 1175 int
 1176 ext2_dirempty(struct inode *ip, ino_t parentino, struct ucred *cred)
 1177 {
 1178         off_t off;
 1179         struct dirtemplate dbuf;
 1180         struct ext2fs_direct_2 *dp = (struct ext2fs_direct_2 *)&dbuf;
 1181         int error, namlen;
 1182         ssize_t count;
 1183 #define MINDIRSIZ (sizeof(struct dirtemplate) / 2)
 1184 
 1185         for (off = 0; off < ip->i_size; off += dp->e2d_reclen) {
 1186                 error = vn_rdwr(UIO_READ, ITOV(ip), (caddr_t)dp, MINDIRSIZ,
 1187                     off, UIO_SYSSPACE, IO_NODELOCKED | IO_NOMACCHECK, cred,
 1188                     NOCRED, &count, (struct thread *)0);
 1189                 /*
 1190                  * Since we read MINDIRSIZ, residual must
 1191                  * be 0 unless we're at end of file.
 1192                  */
 1193                 if (error || count != 0)
 1194                         return (0);
 1195                 /* avoid infinite loops */
 1196                 if (dp->e2d_reclen == 0)
 1197                         return (0);
 1198                 /* skip empty entries */
 1199                 if (dp->e2d_ino == 0)
 1200                         continue;
 1201                 /* accept only "." and ".." */
 1202                 namlen = dp->e2d_namlen;
 1203                 if (namlen > 2)
 1204                         return (0);
 1205                 if (dp->e2d_name[0] != '.')
 1206                         return (0);
 1207                 /*
 1208                  * At this point namlen must be 1 or 2.
 1209                  * 1 implies ".", 2 implies ".." if second
 1210                  * char is also "."
 1211                  */
 1212                 if (namlen == 1)
 1213                         continue;
 1214                 if (dp->e2d_name[1] == '.' && dp->e2d_ino == parentino)
 1215                         continue;
 1216                 return (0);
 1217         }
 1218         return (1);
 1219 }
 1220 
 1221 /*
 1222  * Check if source directory is in the path of the target directory.
 1223  * Target is supplied locked, source is unlocked.
 1224  * The target is always vput before returning.
 1225  */
 1226 int
 1227 ext2_checkpath(struct inode *source, struct inode *target, struct ucred *cred)
 1228 {
 1229         struct vnode *vp;
 1230         int error, namlen;
 1231         struct dirtemplate dirbuf;
 1232 
 1233         vp = ITOV(target);
 1234         if (target->i_number == source->i_number) {
 1235                 error = EEXIST;
 1236                 goto out;
 1237         }
 1238         if (target->i_number == EXT2_ROOTINO) {
 1239                 error = 0;
 1240                 goto out;
 1241         }
 1242 
 1243         for (;;) {
 1244                 if (vp->v_type != VDIR) {
 1245                         error = ENOTDIR;
 1246                         break;
 1247                 }
 1248                 error = vn_rdwr(UIO_READ, vp, (caddr_t)&dirbuf,
 1249                     sizeof(struct dirtemplate), (off_t)0, UIO_SYSSPACE,
 1250                     IO_NODELOCKED | IO_NOMACCHECK, cred, NOCRED, NULL,
 1251                     NULL);
 1252                 if (error != 0)
 1253                         break;
 1254                 namlen = dirbuf.dotdot_type;    /* like ufs little-endian */
 1255                 if (namlen != 2 ||
 1256                     dirbuf.dotdot_name[0] != '.' ||
 1257                     dirbuf.dotdot_name[1] != '.') {
 1258                         error = ENOTDIR;
 1259                         break;
 1260                 }
 1261                 if (dirbuf.dotdot_ino == source->i_number) {
 1262                         error = EINVAL;
 1263                         break;
 1264                 }
 1265                 if (dirbuf.dotdot_ino == EXT2_ROOTINO)
 1266                         break;
 1267                 vput(vp);
 1268                 if ((error = VFS_VGET(vp->v_mount, dirbuf.dotdot_ino,
 1269                     LK_EXCLUSIVE, &vp)) != 0) {
 1270                         vp = NULL;
 1271                         break;
 1272                 }
 1273         }
 1274 
 1275 out:
 1276         if (error == ENOTDIR)
 1277                 printf("checkpath: .. not a directory\n");
 1278         if (vp != NULL)
 1279                 vput(vp);
 1280         return (error);
 1281 }

Cache object: 87cf82d8c84d55f9fcf0eb0bfd1436ad


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.