The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/ufs/ufs/ufs_lookup.c

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    1 /*-
    2  * Copyright (c) 1989, 1993
    3  *      The Regents of the University of California.  All rights reserved.
    4  * (c) UNIX System Laboratories, Inc.
    5  * All or some portions of this file are derived from material licensed
    6  * to the University of California by American Telephone and Telegraph
    7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
    8  * the permission of UNIX System Laboratories, Inc.
    9  *
   10  * Redistribution and use in source and binary forms, with or without
   11  * modification, are permitted provided that the following conditions
   12  * are met:
   13  * 1. Redistributions of source code must retain the above copyright
   14  *    notice, this list of conditions and the following disclaimer.
   15  * 2. Redistributions in binary form must reproduce the above copyright
   16  *    notice, this list of conditions and the following disclaimer in the
   17  *    documentation and/or other materials provided with the distribution.
   18  * 4. Neither the name of the University nor the names of its contributors
   19  *    may be used to endorse or promote products derived from this software
   20  *    without specific prior written permission.
   21  *
   22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   32  * SUCH DAMAGE.
   33  *
   34  *      @(#)ufs_lookup.c        8.15 (Berkeley) 6/16/95
   35  */
   36 
   37 #include <sys/cdefs.h>
   38 __FBSDID("$FreeBSD: releng/11.1/sys/ufs/ufs/ufs_lookup.c 306170 2016-09-22 09:08:11Z kib $");
   39 
   40 #include "opt_ufs.h"
   41 #include "opt_quota.h"
   42 
   43 #include <sys/param.h>
   44 #include <sys/systm.h>
   45 #include <sys/kernel.h>
   46 #include <sys/namei.h>
   47 #include <sys/bio.h>
   48 #include <sys/buf.h>
   49 #include <sys/proc.h>
   50 #include <sys/stat.h>
   51 #include <sys/mount.h>
   52 #include <sys/vnode.h>
   53 #include <sys/sysctl.h>
   54 
   55 #include <vm/vm.h>
   56 #include <vm/vm_extern.h>
   57 
   58 #include <ufs/ufs/extattr.h>
   59 #include <ufs/ufs/quota.h>
   60 #include <ufs/ufs/inode.h>
   61 #include <ufs/ufs/dir.h>
   62 #ifdef UFS_DIRHASH
   63 #include <ufs/ufs/dirhash.h>
   64 #endif
   65 #include <ufs/ufs/ufsmount.h>
   66 #include <ufs/ufs/ufs_extern.h>
   67 
   68 #ifdef DIAGNOSTIC
   69 static int      dirchk = 1;
   70 #else
   71 static int      dirchk = 0;
   72 #endif
   73 
   74 SYSCTL_INT(_debug, OID_AUTO, dircheck, CTLFLAG_RW, &dirchk, 0, "");
   75 
   76 /* true if old FS format...*/
   77 #define OFSFMT(vp)      ((vp)->v_mount->mnt_maxsymlinklen <= 0)
   78 
   79 static int
   80 ufs_delete_denied(struct vnode *vdp, struct vnode *tdp, struct ucred *cred,
   81     struct thread *td)
   82 {
   83         int error;
   84 
   85 #ifdef UFS_ACL
   86         /*
   87          * NFSv4 Minor Version 1, draft-ietf-nfsv4-minorversion1-03.txt
   88          *
   89          * 3.16.2.1. ACE4_DELETE vs. ACE4_DELETE_CHILD
   90          */
   91 
   92         /*
   93          * XXX: Is this check required?
   94          */
   95         error = VOP_ACCESS(vdp, VEXEC, cred, td);
   96         if (error)
   97                 return (error);
   98 
   99         error = VOP_ACCESSX(tdp, VDELETE, cred, td);
  100         if (error == 0)
  101                 return (0);
  102 
  103         error = VOP_ACCESSX(vdp, VDELETE_CHILD, cred, td);
  104         if (error == 0)
  105                 return (0);
  106 
  107         error = VOP_ACCESSX(vdp, VEXPLICIT_DENY | VDELETE_CHILD, cred, td);
  108         if (error)
  109                 return (error);
  110 
  111 #endif /* !UFS_ACL */
  112 
  113         /*
  114          * Standard Unix access control - delete access requires VWRITE.
  115          */
  116         error = VOP_ACCESS(vdp, VWRITE, cred, td);
  117         if (error)
  118                 return (error);
  119 
  120         /*
  121          * If directory is "sticky", then user must own
  122          * the directory, or the file in it, else she
  123          * may not delete it (unless she's root). This
  124          * implements append-only directories.
  125          */
  126         if ((VTOI(vdp)->i_mode & ISVTX) &&
  127             VOP_ACCESS(vdp, VADMIN, cred, td) &&
  128             VOP_ACCESS(tdp, VADMIN, cred, td))
  129                 return (EPERM);
  130 
  131         return (0);
  132 }
  133 
  134 /*
  135  * Convert a component of a pathname into a pointer to a locked inode.
  136  * This is a very central and rather complicated routine.
  137  * If the filesystem is not maintained in a strict tree hierarchy,
  138  * this can result in a deadlock situation (see comments in code below).
  139  *
  140  * The cnp->cn_nameiop argument is LOOKUP, CREATE, RENAME, or DELETE depending
  141  * on whether the name is to be looked up, created, renamed, or deleted.
  142  * When CREATE, RENAME, or DELETE is specified, information usable in
  143  * creating, renaming, or deleting a directory entry may be calculated.
  144  * If flag has LOCKPARENT or'ed into it and the target of the pathname
  145  * exists, lookup returns both the target and its parent directory locked.
  146  * When creating or renaming and LOCKPARENT is specified, the target may
  147  * not be ".".  When deleting and LOCKPARENT is specified, the target may
  148  * be "."., but the caller must check to ensure it does an vrele and vput
  149  * instead of two vputs.
  150  *
  151  * This routine is actually used as VOP_CACHEDLOOKUP method, and the
  152  * filesystem employs the generic vfs_cache_lookup() as VOP_LOOKUP
  153  * method.
  154  *
  155  * vfs_cache_lookup() performs the following for us:
  156  *      check that it is a directory
  157  *      check accessibility of directory
  158  *      check for modification attempts on read-only mounts
  159  *      if name found in cache
  160  *          if at end of path and deleting or creating
  161  *              drop it
  162  *           else
  163  *              return name.
  164  *      return VOP_CACHEDLOOKUP()
  165  *
  166  * Overall outline of ufs_lookup:
  167  *
  168  *      search for name in directory, to found or notfound
  169  * notfound:
  170  *      if creating, return locked directory, leaving info on available slots
  171  *      else return error
  172  * found:
  173  *      if at end of path and deleting, return information to allow delete
  174  *      if at end of path and rewriting (RENAME and LOCKPARENT), lock target
  175  *        inode and return info to allow rewrite
  176  *      if not at end, add name to cache; if at end and neither creating
  177  *        nor deleting, add name to cache
  178  */
  179 int
  180 ufs_lookup(ap)
  181         struct vop_cachedlookup_args /* {
  182                 struct vnode *a_dvp;
  183                 struct vnode **a_vpp;
  184                 struct componentname *a_cnp;
  185         } */ *ap;
  186 {
  187 
  188         return (ufs_lookup_ino(ap->a_dvp, ap->a_vpp, ap->a_cnp, NULL));
  189 }
  190 
  191 int
  192 ufs_lookup_ino(struct vnode *vdp, struct vnode **vpp, struct componentname *cnp,
  193     ino_t *dd_ino)
  194 {
  195         struct inode *dp;               /* inode for directory being searched */
  196         struct buf *bp;                 /* a buffer of directory entries */
  197         struct direct *ep;              /* the current directory entry */
  198         int entryoffsetinblock;         /* offset of ep in bp's buffer */
  199         enum {NONE, COMPACT, FOUND} slotstatus;
  200         doff_t slotoffset;              /* offset of area with free space */
  201         doff_t i_diroff;                /* cached i_diroff value. */
  202         doff_t i_offset;                /* cached i_offset value. */
  203         int slotsize;                   /* size of area at slotoffset */
  204         int slotfreespace;              /* amount of space free in slot */
  205         int slotneeded;                 /* size of the entry we're seeking */
  206         int numdirpasses;               /* strategy for directory search */
  207         doff_t endsearch;               /* offset to end directory search */
  208         doff_t prevoff;                 /* prev entry dp->i_offset */
  209         struct vnode *pdp;              /* saved dp during symlink work */
  210         struct vnode *tdp;              /* returned by VFS_VGET */
  211         doff_t enduseful;               /* pointer past last used dir slot */
  212         u_long bmask;                   /* block offset mask */
  213         int namlen, error;
  214         struct ucred *cred = cnp->cn_cred;
  215         int flags = cnp->cn_flags;
  216         int nameiop = cnp->cn_nameiop;
  217         ino_t ino, ino1;
  218         int ltype;
  219 
  220         if (vpp != NULL)
  221                 *vpp = NULL;
  222 
  223         dp = VTOI(vdp);
  224         if (dp->i_effnlink == 0)
  225                 return (ENOENT);
  226 
  227         /*
  228          * Create a vm object if vmiodirenable is enabled.
  229          * Alternatively we could call vnode_create_vobject
  230          * in VFS_VGET but we could end up creating objects
  231          * that are never used.
  232          */
  233         vnode_create_vobject(vdp, DIP(dp, i_size), cnp->cn_thread);
  234 
  235         bmask = VFSTOUFS(vdp->v_mount)->um_mountp->mnt_stat.f_iosize - 1;
  236 
  237 #ifdef DEBUG_VFS_LOCKS
  238         /*
  239          * Assert that the directory vnode is locked, and locked
  240          * exclusively for the last component lookup for modifying
  241          * operations.
  242          *
  243          * The directory-modifying operations need to save
  244          * intermediate state in the inode between namei() call and
  245          * actual directory manipulations.  See fields in the struct
  246          * inode marked as 'used during directory lookup'.  We must
  247          * ensure that upgrade in namei() does not happen, since
  248          * upgrade might need to unlock vdp.  If quotas are enabled,
  249          * getinoquota() also requires exclusive lock to modify inode.
  250          */
  251         ASSERT_VOP_LOCKED(vdp, "ufs_lookup1");
  252         if ((nameiop == CREATE || nameiop == DELETE || nameiop == RENAME) &&
  253             (flags & (LOCKPARENT | ISLASTCN)) == (LOCKPARENT | ISLASTCN))
  254                 ASSERT_VOP_ELOCKED(vdp, "ufs_lookup2");
  255 #endif
  256 
  257 restart:
  258         bp = NULL;
  259         slotoffset = -1;
  260 
  261         /*
  262          * We now have a segment name to search for, and a directory to search.
  263          *
  264          * Suppress search for slots unless creating
  265          * file and at end of pathname, in which case
  266          * we watch for a place to put the new file in
  267          * case it doesn't already exist.
  268          */
  269         ino = 0;
  270         i_diroff = dp->i_diroff;
  271         slotstatus = FOUND;
  272         slotfreespace = slotsize = slotneeded = 0;
  273         if ((nameiop == CREATE || nameiop == RENAME) &&
  274             (flags & ISLASTCN)) {
  275                 slotstatus = NONE;
  276                 slotneeded = DIRECTSIZ(cnp->cn_namelen);
  277         }
  278 
  279 #ifdef UFS_DIRHASH
  280         /*
  281          * Use dirhash for fast operations on large directories. The logic
  282          * to determine whether to hash the directory is contained within
  283          * ufsdirhash_build(); a zero return means that it decided to hash
  284          * this directory and it successfully built up the hash table.
  285          */
  286         if (ufsdirhash_build(dp) == 0) {
  287                 /* Look for a free slot if needed. */
  288                 enduseful = dp->i_size;
  289                 if (slotstatus != FOUND) {
  290                         slotoffset = ufsdirhash_findfree(dp, slotneeded,
  291                             &slotsize);
  292                         if (slotoffset >= 0) {
  293                                 slotstatus = COMPACT;
  294                                 enduseful = ufsdirhash_enduseful(dp);
  295                                 if (enduseful < 0)
  296                                         enduseful = dp->i_size;
  297                         }
  298                 }
  299                 /* Look up the component. */
  300                 numdirpasses = 1;
  301                 entryoffsetinblock = 0; /* silence compiler warning */
  302                 switch (ufsdirhash_lookup(dp, cnp->cn_nameptr, cnp->cn_namelen,
  303                     &i_offset, &bp, nameiop == DELETE ? &prevoff : NULL)) {
  304                 case 0:
  305                         ep = (struct direct *)((char *)bp->b_data +
  306                             (i_offset & bmask));
  307                         goto foundentry;
  308                 case ENOENT:
  309                         i_offset = roundup2(dp->i_size, DIRBLKSIZ);
  310                         goto notfound;
  311                 default:
  312                         /* Something failed; just do a linear search. */
  313                         break;
  314                 }
  315         }
  316 #endif /* UFS_DIRHASH */
  317         /*
  318          * If there is cached information on a previous search of
  319          * this directory, pick up where we last left off.
  320          * We cache only lookups as these are the most common
  321          * and have the greatest payoff. Caching CREATE has little
  322          * benefit as it usually must search the entire directory
  323          * to determine that the entry does not exist. Caching the
  324          * location of the last DELETE or RENAME has not reduced
  325          * profiling time and hence has been removed in the interest
  326          * of simplicity.
  327          */
  328         if (nameiop != LOOKUP || i_diroff == 0 || i_diroff >= dp->i_size) {
  329                 entryoffsetinblock = 0;
  330                 i_offset = 0;
  331                 numdirpasses = 1;
  332         } else {
  333                 i_offset = i_diroff;
  334                 if ((entryoffsetinblock = i_offset & bmask) &&
  335                     (error = UFS_BLKATOFF(vdp, (off_t)i_offset, NULL, &bp)))
  336                         return (error);
  337                 numdirpasses = 2;
  338                 nchstats.ncs_2passes++;
  339         }
  340         prevoff = i_offset;
  341         endsearch = roundup2(dp->i_size, DIRBLKSIZ);
  342         enduseful = 0;
  343 
  344 searchloop:
  345         while (i_offset < endsearch) {
  346                 /*
  347                  * If necessary, get the next directory block.
  348                  */
  349                 if ((i_offset & bmask) == 0) {
  350                         if (bp != NULL)
  351                                 brelse(bp);
  352                         error =
  353                             UFS_BLKATOFF(vdp, (off_t)i_offset, NULL, &bp);
  354                         if (error)
  355                                 return (error);
  356                         entryoffsetinblock = 0;
  357                 }
  358                 /*
  359                  * If still looking for a slot, and at a DIRBLKSIZE
  360                  * boundary, have to start looking for free space again.
  361                  */
  362                 if (slotstatus == NONE &&
  363                     (entryoffsetinblock & (DIRBLKSIZ - 1)) == 0) {
  364                         slotoffset = -1;
  365                         slotfreespace = 0;
  366                 }
  367                 /*
  368                  * Get pointer to next entry.
  369                  * Full validation checks are slow, so we only check
  370                  * enough to insure forward progress through the
  371                  * directory. Complete checks can be run by patching
  372                  * "dirchk" to be true.
  373                  */
  374                 ep = (struct direct *)((char *)bp->b_data + entryoffsetinblock);
  375                 if (ep->d_reclen == 0 || ep->d_reclen >
  376                     DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1)) ||
  377                     (dirchk && ufs_dirbadentry(vdp, ep, entryoffsetinblock))) {
  378                         int i;
  379 
  380                         ufs_dirbad(dp, i_offset, "mangled entry");
  381                         i = DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1));
  382                         i_offset += i;
  383                         entryoffsetinblock += i;
  384                         continue;
  385                 }
  386 
  387                 /*
  388                  * If an appropriate sized slot has not yet been found,
  389                  * check to see if one is available. Also accumulate space
  390                  * in the current block so that we can determine if
  391                  * compaction is viable.
  392                  */
  393                 if (slotstatus != FOUND) {
  394                         int size = ep->d_reclen;
  395 
  396                         if (ep->d_ino != 0)
  397                                 size -= DIRSIZ(OFSFMT(vdp), ep);
  398                         if (size > 0) {
  399                                 if (size >= slotneeded) {
  400                                         slotstatus = FOUND;
  401                                         slotoffset = i_offset;
  402                                         slotsize = ep->d_reclen;
  403                                 } else if (slotstatus == NONE) {
  404                                         slotfreespace += size;
  405                                         if (slotoffset == -1)
  406                                                 slotoffset = i_offset;
  407                                         if (slotfreespace >= slotneeded) {
  408                                                 slotstatus = COMPACT;
  409                                                 slotsize = i_offset +
  410                                                       ep->d_reclen - slotoffset;
  411                                         }
  412                                 }
  413                         }
  414                 }
  415 
  416                 /*
  417                  * Check for a name match.
  418                  */
  419                 if (ep->d_ino) {
  420 #                       if (BYTE_ORDER == LITTLE_ENDIAN)
  421                                 if (OFSFMT(vdp))
  422                                         namlen = ep->d_type;
  423                                 else
  424                                         namlen = ep->d_namlen;
  425 #                       else
  426                                 namlen = ep->d_namlen;
  427 #                       endif
  428                         if (namlen == cnp->cn_namelen &&
  429                                 (cnp->cn_nameptr[0] == ep->d_name[0]) &&
  430                             !bcmp(cnp->cn_nameptr, ep->d_name,
  431                                 (unsigned)namlen)) {
  432 #ifdef UFS_DIRHASH
  433 foundentry:
  434 #endif
  435                                 /*
  436                                  * Save directory entry's inode number and
  437                                  * reclen in ndp->ni_ufs area, and release
  438                                  * directory buffer.
  439                                  */
  440                                 if (vdp->v_mount->mnt_maxsymlinklen > 0 &&
  441                                     ep->d_type == DT_WHT) {
  442                                         slotstatus = FOUND;
  443                                         slotoffset = i_offset;
  444                                         slotsize = ep->d_reclen;
  445                                         enduseful = dp->i_size;
  446                                         cnp->cn_flags |= ISWHITEOUT;
  447                                         numdirpasses--;
  448                                         goto notfound;
  449                                 }
  450                                 ino = ep->d_ino;
  451                                 goto found;
  452                         }
  453                 }
  454                 prevoff = i_offset;
  455                 i_offset += ep->d_reclen;
  456                 entryoffsetinblock += ep->d_reclen;
  457                 if (ep->d_ino)
  458                         enduseful = i_offset;
  459         }
  460 notfound:
  461         /*
  462          * If we started in the middle of the directory and failed
  463          * to find our target, we must check the beginning as well.
  464          */
  465         if (numdirpasses == 2) {
  466                 numdirpasses--;
  467                 i_offset = 0;
  468                 endsearch = i_diroff;
  469                 goto searchloop;
  470         }
  471         if (bp != NULL)
  472                 brelse(bp);
  473         /*
  474          * If creating, and at end of pathname and current
  475          * directory has not been removed, then can consider
  476          * allowing file to be created.
  477          */
  478         if ((nameiop == CREATE || nameiop == RENAME ||
  479              (nameiop == DELETE &&
  480               (cnp->cn_flags & DOWHITEOUT) &&
  481               (cnp->cn_flags & ISWHITEOUT))) &&
  482             (flags & ISLASTCN) && dp->i_effnlink != 0) {
  483                 /*
  484                  * Access for write is interpreted as allowing
  485                  * creation of files in the directory.
  486                  *
  487                  * XXX: Fix the comment above.
  488                  */
  489                 if (flags & WILLBEDIR)
  490                         error = VOP_ACCESSX(vdp, VWRITE | VAPPEND, cred, cnp->cn_thread);
  491                 else
  492                         error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread);
  493                 if (error)
  494                         return (error);
  495                 /*
  496                  * Return an indication of where the new directory
  497                  * entry should be put.  If we didn't find a slot,
  498                  * then set dp->i_count to 0 indicating
  499                  * that the new slot belongs at the end of the
  500                  * directory. If we found a slot, then the new entry
  501                  * can be put in the range from dp->i_offset to
  502                  * dp->i_offset + dp->i_count.
  503                  */
  504                 if (slotstatus == NONE) {
  505                         dp->i_offset = roundup2(dp->i_size, DIRBLKSIZ);
  506                         dp->i_count = 0;
  507                         enduseful = dp->i_offset;
  508                 } else if (nameiop == DELETE) {
  509                         dp->i_offset = slotoffset;
  510                         if ((dp->i_offset & (DIRBLKSIZ - 1)) == 0)
  511                                 dp->i_count = 0;
  512                         else
  513                                 dp->i_count = dp->i_offset - prevoff;
  514                 } else {
  515                         dp->i_offset = slotoffset;
  516                         dp->i_count = slotsize;
  517                         if (enduseful < slotoffset + slotsize)
  518                                 enduseful = slotoffset + slotsize;
  519                 }
  520                 dp->i_endoff = roundup2(enduseful, DIRBLKSIZ);
  521                 /*
  522                  * We return with the directory locked, so that
  523                  * the parameters we set up above will still be
  524                  * valid if we actually decide to do a direnter().
  525                  * We return ni_vp == NULL to indicate that the entry
  526                  * does not currently exist; we leave a pointer to
  527                  * the (locked) directory inode in ndp->ni_dvp.
  528                  * The pathname buffer is saved so that the name
  529                  * can be obtained later.
  530                  *
  531                  * NB - if the directory is unlocked, then this
  532                  * information cannot be used.
  533                  */
  534                 cnp->cn_flags |= SAVENAME;
  535                 return (EJUSTRETURN);
  536         }
  537         /*
  538          * Insert name into cache (as non-existent) if appropriate.
  539          */
  540         if ((cnp->cn_flags & MAKEENTRY) != 0)
  541                 cache_enter(vdp, NULL, cnp);
  542         return (ENOENT);
  543 
  544 found:
  545         if (dd_ino != NULL)
  546                 *dd_ino = ino;
  547         if (numdirpasses == 2)
  548                 nchstats.ncs_pass2++;
  549         /*
  550          * Check that directory length properly reflects presence
  551          * of this entry.
  552          */
  553         if (i_offset + DIRSIZ(OFSFMT(vdp), ep) > dp->i_size) {
  554                 ufs_dirbad(dp, i_offset, "i_size too small");
  555                 dp->i_size = i_offset + DIRSIZ(OFSFMT(vdp), ep);
  556                 DIP_SET(dp, i_size, dp->i_size);
  557                 dp->i_flag |= IN_CHANGE | IN_UPDATE;
  558         }
  559         brelse(bp);
  560 
  561         /*
  562          * Found component in pathname.
  563          * If the final component of path name, save information
  564          * in the cache as to where the entry was found.
  565          */
  566         if ((flags & ISLASTCN) && nameiop == LOOKUP)
  567                 dp->i_diroff = rounddown2(i_offset, DIRBLKSIZ);
  568 
  569         /*
  570          * If deleting, and at end of pathname, return
  571          * parameters which can be used to remove file.
  572          */
  573         if (nameiop == DELETE && (flags & ISLASTCN)) {
  574                 if (flags & LOCKPARENT)
  575                         ASSERT_VOP_ELOCKED(vdp, __FUNCTION__);
  576                 /*
  577                  * Return pointer to current entry in dp->i_offset,
  578                  * and distance past previous entry (if there
  579                  * is a previous entry in this block) in dp->i_count.
  580                  * Save directory inode pointer in ndp->ni_dvp for dirremove().
  581                  *
  582                  * Technically we shouldn't be setting these in the
  583                  * WANTPARENT case (first lookup in rename()), but any
  584                  * lookups that will result in directory changes will
  585                  * overwrite these.
  586                  */
  587                 dp->i_offset = i_offset;
  588                 if ((dp->i_offset & (DIRBLKSIZ - 1)) == 0)
  589                         dp->i_count = 0;
  590                 else
  591                         dp->i_count = dp->i_offset - prevoff;
  592                 if (dd_ino != NULL)
  593                         return (0);
  594                 if ((error = VFS_VGET(vdp->v_mount, ino,
  595                     LK_EXCLUSIVE, &tdp)) != 0)
  596                         return (error);
  597                 error = ufs_delete_denied(vdp, tdp, cred, cnp->cn_thread);
  598                 if (error) {
  599                         vput(tdp);
  600                         return (error);
  601                 }
  602                 if (dp->i_number == ino) {
  603                         VREF(vdp);
  604                         *vpp = vdp;
  605                         vput(tdp);
  606                         return (0);
  607                 }
  608 
  609                 *vpp = tdp;
  610                 return (0);
  611         }
  612 
  613         /*
  614          * If rewriting (RENAME), return the inode and the
  615          * information required to rewrite the present directory
  616          * Must get inode of directory entry to verify it's a
  617          * regular file, or empty directory.
  618          */
  619         if (nameiop == RENAME && (flags & ISLASTCN)) {
  620                 if (flags & WILLBEDIR)
  621                         error = VOP_ACCESSX(vdp, VWRITE | VAPPEND, cred, cnp->cn_thread);
  622                 else
  623                         error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread);
  624                 if (error)
  625                         return (error);
  626                 /*
  627                  * Careful about locking second inode.
  628                  * This can only occur if the target is ".".
  629                  */
  630                 dp->i_offset = i_offset;
  631                 if (dp->i_number == ino)
  632                         return (EISDIR);
  633                 if (dd_ino != NULL)
  634                         return (0);
  635                 if ((error = VFS_VGET(vdp->v_mount, ino,
  636                     LK_EXCLUSIVE, &tdp)) != 0)
  637                         return (error);
  638 
  639                 error = ufs_delete_denied(vdp, tdp, cred, cnp->cn_thread);
  640                 if (error) {
  641                         vput(tdp);
  642                         return (error);
  643                 }
  644 
  645 #ifdef SunOS_doesnt_do_that
  646                 /*
  647                  * The only purpose of this check is to return the correct
  648                  * error.  Assume that we want to rename directory "a"
  649                  * to a file "b", and that we have no ACL_WRITE_DATA on
  650                  * a containing directory, but we _do_ have ACL_APPEND_DATA. 
  651                  * In that case, the VOP_ACCESS check above will return 0,
  652                  * and the operation will fail with ENOTDIR instead
  653                  * of EACCESS.
  654                  */
  655                 if (tdp->v_type == VDIR)
  656                         error = VOP_ACCESSX(vdp, VWRITE | VAPPEND, cred, cnp->cn_thread);
  657                 else
  658                         error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread);
  659                 if (error) {
  660                         vput(tdp);
  661                         return (error);
  662                 }
  663 #endif
  664 
  665                 *vpp = tdp;
  666                 cnp->cn_flags |= SAVENAME;
  667                 return (0);
  668         }
  669         if (dd_ino != NULL)
  670                 return (0);
  671 
  672         /*
  673          * Step through the translation in the name.  We do not `vput' the
  674          * directory because we may need it again if a symbolic link
  675          * is relative to the current directory.  Instead we save it
  676          * unlocked as "pdp".  We must get the target inode before unlocking
  677          * the directory to insure that the inode will not be removed
  678          * before we get it.  We prevent deadlock by always fetching
  679          * inodes from the root, moving down the directory tree. Thus
  680          * when following backward pointers ".." we must unlock the
  681          * parent directory before getting the requested directory.
  682          * There is a potential race condition here if both the current
  683          * and parent directories are removed before the VFS_VGET for the
  684          * inode associated with ".." returns.  We hope that this occurs
  685          * infrequently since we cannot avoid this race condition without
  686          * implementing a sophisticated deadlock detection algorithm.
  687          * Note also that this simple deadlock detection scheme will not
  688          * work if the filesystem has any hard links other than ".."
  689          * that point backwards in the directory structure.
  690          */
  691         pdp = vdp;
  692         if (flags & ISDOTDOT) {
  693                 error = vn_vget_ino(pdp, ino, cnp->cn_lkflags, &tdp);
  694                 if (error)
  695                         return (error);
  696 
  697                 /*
  698                  * Recheck that ".." entry in the vdp directory points
  699                  * to the inode we looked up before vdp lock was
  700                  * dropped.
  701                  */
  702                 error = ufs_lookup_ino(pdp, NULL, cnp, &ino1);
  703                 if (error) {
  704                         vput(tdp);
  705                         return (error);
  706                 }
  707                 if (ino1 != ino) {
  708                         vput(tdp);
  709                         goto restart;
  710                 }
  711 
  712                 *vpp = tdp;
  713         } else if (dp->i_number == ino) {
  714                 VREF(vdp);      /* we want ourself, ie "." */
  715                 /*
  716                  * When we lookup "." we still can be asked to lock it
  717                  * differently.
  718                  */
  719                 ltype = cnp->cn_lkflags & LK_TYPE_MASK;
  720                 if (ltype != VOP_ISLOCKED(vdp)) {
  721                         if (ltype == LK_EXCLUSIVE)
  722                                 vn_lock(vdp, LK_UPGRADE | LK_RETRY);
  723                         else /* if (ltype == LK_SHARED) */
  724                                 vn_lock(vdp, LK_DOWNGRADE | LK_RETRY);
  725                         /*
  726                          * Relock for the "." case may left us with
  727                          * reclaimed vnode.
  728                          */
  729                         if (vdp->v_iflag & VI_DOOMED) {
  730                                 vrele(vdp);
  731                                 return (ENOENT);
  732                         }
  733                 }
  734                 *vpp = vdp;
  735         } else {
  736                 error = VFS_VGET(pdp->v_mount, ino, cnp->cn_lkflags, &tdp);
  737                 if (error)
  738                         return (error);
  739                 *vpp = tdp;
  740         }
  741 
  742         /*
  743          * Insert name into cache if appropriate.
  744          */
  745         if (cnp->cn_flags & MAKEENTRY)
  746                 cache_enter(vdp, *vpp, cnp);
  747         return (0);
  748 }
  749 
  750 void
  751 ufs_dirbad(ip, offset, how)
  752         struct inode *ip;
  753         doff_t offset;
  754         char *how;
  755 {
  756         struct mount *mp;
  757 
  758         mp = ITOV(ip)->v_mount;
  759         if ((mp->mnt_flag & MNT_RDONLY) == 0)
  760                 panic("ufs_dirbad: %s: bad dir ino %ju at offset %ld: %s",
  761                     mp->mnt_stat.f_mntonname, (uintmax_t)ip->i_number,
  762                     (long)offset, how);
  763         else
  764                 (void)printf("%s: bad dir ino %ju at offset %ld: %s\n",
  765                     mp->mnt_stat.f_mntonname, (uintmax_t)ip->i_number,
  766                     (long)offset, how);
  767 }
  768 
  769 /*
  770  * Do consistency checking on a directory entry:
  771  *      record length must be multiple of 4
  772  *      entry must fit in rest of its DIRBLKSIZ block
  773  *      record must be large enough to contain entry
  774  *      name is not longer than MAXNAMLEN
  775  *      name must be as long as advertised, and null terminated
  776  */
  777 int
  778 ufs_dirbadentry(dp, ep, entryoffsetinblock)
  779         struct vnode *dp;
  780         struct direct *ep;
  781         int entryoffsetinblock;
  782 {
  783         int i, namlen;
  784 
  785 #       if (BYTE_ORDER == LITTLE_ENDIAN)
  786                 if (OFSFMT(dp))
  787                         namlen = ep->d_type;
  788                 else
  789                         namlen = ep->d_namlen;
  790 #       else
  791                 namlen = ep->d_namlen;
  792 #       endif
  793         if ((ep->d_reclen & 0x3) != 0 ||
  794             ep->d_reclen > DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1)) ||
  795             ep->d_reclen < DIRSIZ(OFSFMT(dp), ep) || namlen > MAXNAMLEN) {
  796                 /*return (1); */
  797                 printf("First bad\n");
  798                 goto bad;
  799         }
  800         if (ep->d_ino == 0)
  801                 return (0);
  802         for (i = 0; i < namlen; i++)
  803                 if (ep->d_name[i] == '\0') {
  804                         /*return (1); */
  805                         printf("Second bad\n");
  806                         goto bad;
  807                 }
  808         if (ep->d_name[i])
  809                 goto bad;
  810         return (0);
  811 bad:
  812         return (1);
  813 }
  814 
  815 /*
  816  * Construct a new directory entry after a call to namei, using the
  817  * parameters that it left in the componentname argument cnp. The
  818  * argument ip is the inode to which the new directory entry will refer.
  819  */
  820 void
  821 ufs_makedirentry(ip, cnp, newdirp)
  822         struct inode *ip;
  823         struct componentname *cnp;
  824         struct direct *newdirp;
  825 {
  826 
  827 #ifdef INVARIANTS
  828         if ((cnp->cn_flags & SAVENAME) == 0)
  829                 panic("ufs_makedirentry: missing name");
  830 #endif
  831         newdirp->d_ino = ip->i_number;
  832         newdirp->d_namlen = cnp->cn_namelen;
  833         bcopy(cnp->cn_nameptr, newdirp->d_name, (unsigned)cnp->cn_namelen + 1);
  834         if (ITOV(ip)->v_mount->mnt_maxsymlinklen > 0)
  835                 newdirp->d_type = IFTODT(ip->i_mode);
  836         else {
  837                 newdirp->d_type = 0;
  838 #               if (BYTE_ORDER == LITTLE_ENDIAN)
  839                         { u_char tmp = newdirp->d_namlen;
  840                         newdirp->d_namlen = newdirp->d_type;
  841                         newdirp->d_type = tmp; }
  842 #               endif
  843         }
  844 }
  845 
  846 /*
  847  * Write a directory entry after a call to namei, using the parameters
  848  * that it left in nameidata. The argument dirp is the new directory
  849  * entry contents. Dvp is a pointer to the directory to be written,
  850  * which was left locked by namei. Remaining parameters (dp->i_offset, 
  851  * dp->i_count) indicate how the space for the new entry is to be obtained.
  852  * Non-null bp indicates that a directory is being created (for the
  853  * soft dependency code).
  854  */
  855 int
  856 ufs_direnter(dvp, tvp, dirp, cnp, newdirbp, isrename)
  857         struct vnode *dvp;
  858         struct vnode *tvp;
  859         struct direct *dirp;
  860         struct componentname *cnp;
  861         struct buf *newdirbp;
  862         int isrename;
  863 {
  864         struct ucred *cr;
  865         struct thread *td;
  866         int newentrysize;
  867         struct inode *dp;
  868         struct buf *bp;
  869         u_int dsize;
  870         struct direct *ep, *nep;
  871         u_int64_t old_isize;
  872         int error, ret, blkoff, loc, spacefree, flags, namlen;
  873         char *dirbuf;
  874 
  875         td = curthread; /* XXX */
  876         cr = td->td_ucred;
  877 
  878         dp = VTOI(dvp);
  879         newentrysize = DIRSIZ(OFSFMT(dvp), dirp);
  880 
  881         if (dp->i_count == 0) {
  882                 /*
  883                  * If dp->i_count is 0, then namei could find no
  884                  * space in the directory. Here, dp->i_offset will
  885                  * be on a directory block boundary and we will write the
  886                  * new entry into a fresh block.
  887                  */
  888                 if (dp->i_offset & (DIRBLKSIZ - 1))
  889                         panic("ufs_direnter: newblk");
  890                 flags = BA_CLRBUF;
  891                 if (!DOINGSOFTDEP(dvp) && !DOINGASYNC(dvp))
  892                         flags |= IO_SYNC;
  893 #ifdef QUOTA
  894                 if ((error = getinoquota(dp)) != 0) {
  895                         if (DOINGSOFTDEP(dvp) && newdirbp != NULL)
  896                                 bdwrite(newdirbp);
  897                         return (error);
  898                 }
  899 #endif
  900                 old_isize = dp->i_size;
  901                 vnode_pager_setsize(dvp, (u_long)dp->i_offset + DIRBLKSIZ);
  902                 if ((error = UFS_BALLOC(dvp, (off_t)dp->i_offset, DIRBLKSIZ,
  903                     cr, flags, &bp)) != 0) {
  904                         if (DOINGSOFTDEP(dvp) && newdirbp != NULL)
  905                                 bdwrite(newdirbp);
  906                         vnode_pager_setsize(dvp, (u_long)old_isize);
  907                         return (error);
  908                 }
  909                 dp->i_size = dp->i_offset + DIRBLKSIZ;
  910                 DIP_SET(dp, i_size, dp->i_size);
  911                 dp->i_endoff = dp->i_size;
  912                 dp->i_flag |= IN_CHANGE | IN_UPDATE;
  913                 dirp->d_reclen = DIRBLKSIZ;
  914                 blkoff = dp->i_offset &
  915                     (VFSTOUFS(dvp->v_mount)->um_mountp->mnt_stat.f_iosize - 1);
  916                 bcopy((caddr_t)dirp, (caddr_t)bp->b_data + blkoff,newentrysize);
  917 #ifdef UFS_DIRHASH
  918                 if (dp->i_dirhash != NULL) {
  919                         ufsdirhash_newblk(dp, dp->i_offset);
  920                         ufsdirhash_add(dp, dirp, dp->i_offset);
  921                         ufsdirhash_checkblock(dp, (char *)bp->b_data + blkoff,
  922                             dp->i_offset);
  923                 }
  924 #endif
  925                 if (DOINGSOFTDEP(dvp)) {
  926                         /*
  927                          * Ensure that the entire newly allocated block is a
  928                          * valid directory so that future growth within the
  929                          * block does not have to ensure that the block is
  930                          * written before the inode.
  931                          */
  932                         blkoff += DIRBLKSIZ;
  933                         while (blkoff < bp->b_bcount) {
  934                                 ((struct direct *)
  935                                    (bp->b_data + blkoff))->d_reclen = DIRBLKSIZ;
  936                                 blkoff += DIRBLKSIZ;
  937                         }
  938                         if (softdep_setup_directory_add(bp, dp, dp->i_offset,
  939                             dirp->d_ino, newdirbp, 1))
  940                                 dp->i_flag |= IN_NEEDSYNC;
  941                         if (newdirbp)
  942                                 bdwrite(newdirbp);
  943                         bdwrite(bp);
  944                         if ((dp->i_flag & IN_NEEDSYNC) == 0)
  945                                 return (UFS_UPDATE(dvp, 0));
  946                         /*
  947                          * We have just allocated a directory block in an
  948                          * indirect block.  We must prevent holes in the
  949                          * directory created if directory entries are
  950                          * written out of order.  To accomplish this we
  951                          * fsync when we extend a directory into indirects.
  952                          * During rename it's not safe to drop the tvp lock
  953                          * so sync must be delayed until it is.
  954                          *
  955                          * This synchronous step could be removed if fsck and
  956                          * the kernel were taught to fill in sparse
  957                          * directories rather than panic.
  958                          */
  959                         if (isrename)
  960                                 return (0);
  961                         if (tvp != NULL)
  962                                 VOP_UNLOCK(tvp, 0);
  963                         (void) VOP_FSYNC(dvp, MNT_WAIT, td);
  964                         if (tvp != NULL)
  965                                 vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY);
  966                         return (error);
  967                 }
  968                 if (DOINGASYNC(dvp)) {
  969                         bdwrite(bp);
  970                         return (UFS_UPDATE(dvp, 0));
  971                 }
  972                 error = bwrite(bp);
  973                 ret = UFS_UPDATE(dvp, 1);
  974                 if (error == 0)
  975                         return (ret);
  976                 return (error);
  977         }
  978 
  979         /*
  980          * If dp->i_count is non-zero, then namei found space for the new
  981          * entry in the range dp->i_offset to dp->i_offset + dp->i_count
  982          * in the directory. To use this space, we may have to compact
  983          * the entries located there, by copying them together towards the
  984          * beginning of the block, leaving the free space in one usable
  985          * chunk at the end.
  986          */
  987 
  988         /*
  989          * Increase size of directory if entry eats into new space.
  990          * This should never push the size past a new multiple of
  991          * DIRBLKSIZE.
  992          *
  993          * N.B. - THIS IS AN ARTIFACT OF 4.2 AND SHOULD NEVER HAPPEN.
  994          */
  995         if (dp->i_offset + dp->i_count > dp->i_size) {
  996                 dp->i_size = dp->i_offset + dp->i_count;
  997                 DIP_SET(dp, i_size, dp->i_size);
  998         }
  999         /*
 1000          * Get the block containing the space for the new directory entry.
 1001          */
 1002         error = UFS_BLKATOFF(dvp, (off_t)dp->i_offset, &dirbuf, &bp);
 1003         if (error) {
 1004                 if (DOINGSOFTDEP(dvp) && newdirbp != NULL)
 1005                         bdwrite(newdirbp);
 1006                 return (error);
 1007         }
 1008         /*
 1009          * Find space for the new entry. In the simple case, the entry at
 1010          * offset base will have the space. If it does not, then namei
 1011          * arranged that compacting the region dp->i_offset to
 1012          * dp->i_offset + dp->i_count would yield the space.
 1013          */
 1014         ep = (struct direct *)dirbuf;
 1015         dsize = ep->d_ino ? DIRSIZ(OFSFMT(dvp), ep) : 0;
 1016         spacefree = ep->d_reclen - dsize;
 1017         for (loc = ep->d_reclen; loc < dp->i_count; ) {
 1018                 nep = (struct direct *)(dirbuf + loc);
 1019 
 1020                 /* Trim the existing slot (NB: dsize may be zero). */
 1021                 ep->d_reclen = dsize;
 1022                 ep = (struct direct *)((char *)ep + dsize);
 1023 
 1024                 /* Read nep->d_reclen now as the bcopy() may clobber it. */
 1025                 loc += nep->d_reclen;
 1026                 if (nep->d_ino == 0) {
 1027                         /*
 1028                          * A mid-block unused entry. Such entries are
 1029                          * never created by the kernel, but fsck_ffs
 1030                          * can create them (and it doesn't fix them).
 1031                          *
 1032                          * Add up the free space, and initialise the
 1033                          * relocated entry since we don't bcopy it.
 1034                          */
 1035                         spacefree += nep->d_reclen;
 1036                         ep->d_ino = 0;
 1037                         dsize = 0;
 1038                         continue;
 1039                 }
 1040                 dsize = DIRSIZ(OFSFMT(dvp), nep);
 1041                 spacefree += nep->d_reclen - dsize;
 1042 #ifdef UFS_DIRHASH
 1043                 if (dp->i_dirhash != NULL)
 1044                         ufsdirhash_move(dp, nep,
 1045                             dp->i_offset + ((char *)nep - dirbuf),
 1046                             dp->i_offset + ((char *)ep - dirbuf));
 1047 #endif
 1048                 if (DOINGSOFTDEP(dvp))
 1049                         softdep_change_directoryentry_offset(bp, dp, dirbuf,
 1050                             (caddr_t)nep, (caddr_t)ep, dsize); 
 1051                 else
 1052                         bcopy((caddr_t)nep, (caddr_t)ep, dsize);
 1053         }
 1054         /*
 1055          * Here, `ep' points to a directory entry containing `dsize' in-use
 1056          * bytes followed by `spacefree' unused bytes. If ep->d_ino == 0,
 1057          * then the entry is completely unused (dsize == 0). The value
 1058          * of ep->d_reclen is always indeterminate.
 1059          *
 1060          * Update the pointer fields in the previous entry (if any),
 1061          * copy in the new entry, and write out the block.
 1062          */
 1063 #       if (BYTE_ORDER == LITTLE_ENDIAN)
 1064                 if (OFSFMT(dvp))
 1065                         namlen = ep->d_type;
 1066                 else
 1067                         namlen = ep->d_namlen;
 1068 #       else
 1069                 namlen = ep->d_namlen;
 1070 #       endif
 1071         if (ep->d_ino == 0 ||
 1072             (ep->d_ino == WINO && namlen == dirp->d_namlen &&
 1073              bcmp(ep->d_name, dirp->d_name, dirp->d_namlen) == 0)) {
 1074                 if (spacefree + dsize < newentrysize)
 1075                         panic("ufs_direnter: compact1");
 1076                 dirp->d_reclen = spacefree + dsize;
 1077         } else {
 1078                 if (spacefree < newentrysize)
 1079                         panic("ufs_direnter: compact2");
 1080                 dirp->d_reclen = spacefree;
 1081                 ep->d_reclen = dsize;
 1082                 ep = (struct direct *)((char *)ep + dsize);
 1083         }
 1084 #ifdef UFS_DIRHASH
 1085         if (dp->i_dirhash != NULL && (ep->d_ino == 0 ||
 1086             dirp->d_reclen == spacefree))
 1087                 ufsdirhash_add(dp, dirp, dp->i_offset + ((char *)ep - dirbuf));
 1088 #endif
 1089         bcopy((caddr_t)dirp, (caddr_t)ep, (u_int)newentrysize);
 1090 #ifdef UFS_DIRHASH
 1091         if (dp->i_dirhash != NULL)
 1092                 ufsdirhash_checkblock(dp, dirbuf -
 1093                     (dp->i_offset & (DIRBLKSIZ - 1)),
 1094                     rounddown2(dp->i_offset, DIRBLKSIZ));
 1095 #endif
 1096 
 1097         if (DOINGSOFTDEP(dvp)) {
 1098                 (void) softdep_setup_directory_add(bp, dp,
 1099                     dp->i_offset + (caddr_t)ep - dirbuf,
 1100                     dirp->d_ino, newdirbp, 0);
 1101                 if (newdirbp != NULL)
 1102                         bdwrite(newdirbp);
 1103                 bdwrite(bp);
 1104         } else {
 1105                 if (DOINGASYNC(dvp)) {
 1106                         bdwrite(bp);
 1107                         error = 0;
 1108                 } else {
 1109                         error = bwrite(bp);
 1110                 }
 1111         }
 1112         dp->i_flag |= IN_CHANGE | IN_UPDATE;
 1113         /*
 1114          * If all went well, and the directory can be shortened, proceed
 1115          * with the truncation. Note that we have to unlock the inode for
 1116          * the entry that we just entered, as the truncation may need to
 1117          * lock other inodes which can lead to deadlock if we also hold a
 1118          * lock on the newly entered node.
 1119          */
 1120         if (isrename == 0 && error == 0 &&
 1121             dp->i_endoff && dp->i_endoff < dp->i_size) {
 1122                 if (tvp != NULL)
 1123                         VOP_UNLOCK(tvp, 0);
 1124                 error = UFS_TRUNCATE(dvp, (off_t)dp->i_endoff,
 1125                     IO_NORMAL | (DOINGASYNC(dvp) ? 0 : IO_SYNC), cr);
 1126                 if (error != 0)
 1127                         vn_printf(dvp, "ufs_direnter: failed to truncate "
 1128                             "err %d", error);
 1129 #ifdef UFS_DIRHASH
 1130                 if (error == 0 && dp->i_dirhash != NULL)
 1131                         ufsdirhash_dirtrunc(dp, dp->i_endoff);
 1132 #endif
 1133                 error = 0;
 1134                 if (tvp != NULL)
 1135                         vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY);
 1136         }
 1137         return (error);
 1138 }
 1139 
 1140 /*
 1141  * Remove a directory entry after a call to namei, using
 1142  * the parameters which it left in nameidata. The entry
 1143  * dp->i_offset contains the offset into the directory of the
 1144  * entry to be eliminated.  The dp->i_count field contains the
 1145  * size of the previous record in the directory.  If this
 1146  * is 0, the first entry is being deleted, so we need only
 1147  * zero the inode number to mark the entry as free.  If the
 1148  * entry is not the first in the directory, we must reclaim
 1149  * the space of the now empty record by adding the record size
 1150  * to the size of the previous entry.
 1151  */
 1152 int
 1153 ufs_dirremove(dvp, ip, flags, isrmdir)
 1154         struct vnode *dvp;
 1155         struct inode *ip;
 1156         int flags;
 1157         int isrmdir;
 1158 {
 1159         struct inode *dp;
 1160         struct direct *ep, *rep;
 1161         struct buf *bp;
 1162         int error;
 1163 
 1164         dp = VTOI(dvp);
 1165 
 1166         /*
 1167          * Adjust the link count early so softdep can block if necessary.
 1168          */
 1169         if (ip) {
 1170                 ip->i_effnlink--;
 1171                 if (DOINGSOFTDEP(dvp)) {
 1172                         softdep_setup_unlink(dp, ip);
 1173                 } else {
 1174                         ip->i_nlink--;
 1175                         DIP_SET(ip, i_nlink, ip->i_nlink);
 1176                         ip->i_flag |= IN_CHANGE;
 1177                 }
 1178         }
 1179         if (flags & DOWHITEOUT) {
 1180                 /*
 1181                  * Whiteout entry: set d_ino to WINO.
 1182                  */
 1183                 if ((error =
 1184                     UFS_BLKATOFF(dvp, (off_t)dp->i_offset, (char **)&ep, &bp)) != 0)
 1185                         return (error);
 1186                 ep->d_ino = WINO;
 1187                 ep->d_type = DT_WHT;
 1188                 goto out;
 1189         }
 1190 
 1191         if ((error = UFS_BLKATOFF(dvp,
 1192             (off_t)(dp->i_offset - dp->i_count), (char **)&ep, &bp)) != 0)
 1193                 return (error);
 1194 
 1195         /* Set 'rep' to the entry being removed. */
 1196         if (dp->i_count == 0)
 1197                 rep = ep;
 1198         else
 1199                 rep = (struct direct *)((char *)ep + ep->d_reclen);
 1200 #ifdef UFS_DIRHASH
 1201         /*
 1202          * Remove the dirhash entry. This is complicated by the fact
 1203          * that `ep' is the previous entry when dp->i_count != 0.
 1204          */
 1205         if (dp->i_dirhash != NULL)
 1206                 ufsdirhash_remove(dp, rep, dp->i_offset);
 1207 #endif
 1208         if (ip && rep->d_ino != ip->i_number)
 1209                 panic("ufs_dirremove: ip %ju does not match dirent ino %ju\n",
 1210                     (uintmax_t)ip->i_number, (uintmax_t)rep->d_ino);
 1211         if (dp->i_count == 0) {
 1212                 /*
 1213                  * First entry in block: set d_ino to zero.
 1214                  */
 1215                 ep->d_ino = 0;
 1216         } else {
 1217                 /*
 1218                  * Collapse new free space into previous entry.
 1219                  */
 1220                 ep->d_reclen += rep->d_reclen;
 1221         }
 1222 #ifdef UFS_DIRHASH
 1223         if (dp->i_dirhash != NULL)
 1224                 ufsdirhash_checkblock(dp, (char *)ep -
 1225                     ((dp->i_offset - dp->i_count) & (DIRBLKSIZ - 1)),
 1226                     rounddown2(dp->i_offset, DIRBLKSIZ));
 1227 #endif
 1228 out:
 1229         error = 0;
 1230         if (DOINGSOFTDEP(dvp)) {
 1231                 if (ip)
 1232                         softdep_setup_remove(bp, dp, ip, isrmdir);
 1233                 if (softdep_slowdown(dvp))
 1234                         error = bwrite(bp);
 1235                 else
 1236                         bdwrite(bp);
 1237         } else {
 1238                 if (flags & DOWHITEOUT)
 1239                         error = bwrite(bp);
 1240                 else if (DOINGASYNC(dvp) && dp->i_count != 0)
 1241                         bdwrite(bp);
 1242                 else
 1243                         error = bwrite(bp);
 1244         }
 1245         dp->i_flag |= IN_CHANGE | IN_UPDATE;
 1246         /*
 1247          * If the last named reference to a snapshot goes away,
 1248          * drop its snapshot reference so that it will be reclaimed
 1249          * when last open reference goes away.
 1250          */
 1251         if (ip != NULL && (ip->i_flags & SF_SNAPSHOT) != 0 &&
 1252             ip->i_effnlink == 0)
 1253                 UFS_SNAPGONE(ip);
 1254         return (error);
 1255 }
 1256 
 1257 /*
 1258  * Rewrite an existing directory entry to point at the inode
 1259  * supplied.  The parameters describing the directory entry are
 1260  * set up by a call to namei.
 1261  */
 1262 int
 1263 ufs_dirrewrite(dp, oip, newinum, newtype, isrmdir)
 1264         struct inode *dp, *oip;
 1265         ino_t newinum;
 1266         int newtype;
 1267         int isrmdir;
 1268 {
 1269         struct buf *bp;
 1270         struct direct *ep;
 1271         struct vnode *vdp = ITOV(dp);
 1272         int error;
 1273 
 1274         /*
 1275          * Drop the link before we lock the buf so softdep can block if
 1276          * necessary.
 1277          */
 1278         oip->i_effnlink--;
 1279         if (DOINGSOFTDEP(vdp)) {
 1280                 softdep_setup_unlink(dp, oip);
 1281         } else {
 1282                 oip->i_nlink--;
 1283                 DIP_SET(oip, i_nlink, oip->i_nlink);
 1284                 oip->i_flag |= IN_CHANGE;
 1285         }
 1286 
 1287         error = UFS_BLKATOFF(vdp, (off_t)dp->i_offset, (char **)&ep, &bp);
 1288         if (error)
 1289                 return (error);
 1290         if (ep->d_namlen == 2 && ep->d_name[1] == '.' && ep->d_name[0] == '.' &&
 1291             ep->d_ino != oip->i_number) {
 1292                 brelse(bp);
 1293                 return (EIDRM);
 1294         }
 1295         ep->d_ino = newinum;
 1296         if (!OFSFMT(vdp))
 1297                 ep->d_type = newtype;
 1298         if (DOINGSOFTDEP(vdp)) {
 1299                 softdep_setup_directory_change(bp, dp, oip, newinum, isrmdir);
 1300                 bdwrite(bp);
 1301         } else {
 1302                 if (DOINGASYNC(vdp)) {
 1303                         bdwrite(bp);
 1304                         error = 0;
 1305                 } else {
 1306                         error = bwrite(bp);
 1307                 }
 1308         }
 1309         dp->i_flag |= IN_CHANGE | IN_UPDATE;
 1310         /*
 1311          * If the last named reference to a snapshot goes away,
 1312          * drop its snapshot reference so that it will be reclaimed
 1313          * when last open reference goes away.
 1314          */
 1315         if ((oip->i_flags & SF_SNAPSHOT) != 0 && oip->i_effnlink == 0)
 1316                 UFS_SNAPGONE(oip);
 1317         return (error);
 1318 }
 1319 
 1320 /*
 1321  * Check if a directory is empty or not.
 1322  * Inode supplied must be locked.
 1323  *
 1324  * Using a struct dirtemplate here is not precisely
 1325  * what we want, but better than using a struct direct.
 1326  *
 1327  * NB: does not handle corrupted directories.
 1328  */
 1329 int
 1330 ufs_dirempty(ip, parentino, cred)
 1331         struct inode *ip;
 1332         ino_t parentino;
 1333         struct ucred *cred;
 1334 {
 1335         doff_t off;
 1336         struct dirtemplate dbuf;
 1337         struct direct *dp = (struct direct *)&dbuf;
 1338         int error, namlen;
 1339         ssize_t count;
 1340 #define MINDIRSIZ (sizeof (struct dirtemplate) / 2)
 1341 
 1342         for (off = 0; off < ip->i_size; off += dp->d_reclen) {
 1343                 error = vn_rdwr(UIO_READ, ITOV(ip), (caddr_t)dp, MINDIRSIZ,
 1344                     off, UIO_SYSSPACE, IO_NODELOCKED | IO_NOMACCHECK, cred,
 1345                     NOCRED, &count, (struct thread *)0);
 1346                 /*
 1347                  * Since we read MINDIRSIZ, residual must
 1348                  * be 0 unless we're at end of file.
 1349                  */
 1350                 if (error || count != 0)
 1351                         return (0);
 1352                 /* avoid infinite loops */
 1353                 if (dp->d_reclen == 0)
 1354                         return (0);
 1355                 /* skip empty entries */
 1356                 if (dp->d_ino == 0 || dp->d_ino == WINO)
 1357                         continue;
 1358                 /* accept only "." and ".." */
 1359 #               if (BYTE_ORDER == LITTLE_ENDIAN)
 1360                         if (OFSFMT(ITOV(ip)))
 1361                                 namlen = dp->d_type;
 1362                         else
 1363                                 namlen = dp->d_namlen;
 1364 #               else
 1365                         namlen = dp->d_namlen;
 1366 #               endif
 1367                 if (namlen > 2)
 1368                         return (0);
 1369                 if (dp->d_name[0] != '.')
 1370                         return (0);
 1371                 /*
 1372                  * At this point namlen must be 1 or 2.
 1373                  * 1 implies ".", 2 implies ".." if second
 1374                  * char is also "."
 1375                  */
 1376                 if (namlen == 1 && dp->d_ino == ip->i_number)
 1377                         continue;
 1378                 if (dp->d_name[1] == '.' && dp->d_ino == parentino)
 1379                         continue;
 1380                 return (0);
 1381         }
 1382         return (1);
 1383 }
 1384 
 1385 static int
 1386 ufs_dir_dd_ino(struct vnode *vp, struct ucred *cred, ino_t *dd_ino,
 1387     struct vnode **dd_vp)
 1388 {
 1389         struct dirtemplate dirbuf;
 1390         struct vnode *ddvp;
 1391         int error, namlen;
 1392 
 1393         ASSERT_VOP_LOCKED(vp, "ufs_dir_dd_ino");
 1394         if (vp->v_type != VDIR)
 1395                 return (ENOTDIR);
 1396         /*
 1397          * First check to see if we have it in the name cache.
 1398          */
 1399         if ((ddvp = vn_dir_dd_ino(vp)) != NULL) {
 1400                 KASSERT(ddvp->v_mount == vp->v_mount,
 1401                     ("ufs_dir_dd_ino: Unexpected mount point crossing"));
 1402                 *dd_ino = VTOI(ddvp)->i_number;
 1403                 *dd_vp = ddvp;
 1404                 return (0);
 1405         }
 1406         /*
 1407          * Have to read the directory.
 1408          */
 1409         error = vn_rdwr(UIO_READ, vp, (caddr_t)&dirbuf,
 1410             sizeof (struct dirtemplate), (off_t)0, UIO_SYSSPACE,
 1411             IO_NODELOCKED | IO_NOMACCHECK, cred, NOCRED, NULL, NULL);
 1412         if (error != 0)
 1413                 return (error);
 1414 #if (BYTE_ORDER == LITTLE_ENDIAN)
 1415         if (OFSFMT(vp))
 1416                 namlen = dirbuf.dotdot_type;
 1417         else
 1418                 namlen = dirbuf.dotdot_namlen;
 1419 #else
 1420         namlen = dirbuf.dotdot_namlen;
 1421 #endif
 1422         if (namlen != 2 || dirbuf.dotdot_name[0] != '.' ||
 1423             dirbuf.dotdot_name[1] != '.')
 1424                 return (ENOTDIR);
 1425         *dd_ino = dirbuf.dotdot_ino;
 1426         *dd_vp = NULL;
 1427         return (0);
 1428 }
 1429 
 1430 /*
 1431  * Check if source directory is in the path of the target directory.
 1432  */
 1433 int
 1434 ufs_checkpath(ino_t source_ino, ino_t parent_ino, struct inode *target, struct ucred *cred, ino_t *wait_ino)
 1435 {
 1436         struct mount *mp;
 1437         struct vnode *tvp, *vp, *vp1;
 1438         int error;
 1439         ino_t dd_ino;
 1440 
 1441         vp = tvp = ITOV(target);
 1442         mp = vp->v_mount;
 1443         *wait_ino = 0;
 1444         if (target->i_number == source_ino)
 1445                 return (EEXIST);
 1446         if (target->i_number == parent_ino)
 1447                 return (0);
 1448         if (target->i_number == ROOTINO)
 1449                 return (0);
 1450         for (;;) {
 1451                 error = ufs_dir_dd_ino(vp, cred, &dd_ino, &vp1);
 1452                 if (error != 0)
 1453                         break;
 1454                 if (dd_ino == source_ino) {
 1455                         error = EINVAL;
 1456                         break;
 1457                 }
 1458                 if (dd_ino == ROOTINO)
 1459                         break;
 1460                 if (dd_ino == parent_ino)
 1461                         break;
 1462                 if (vp1 == NULL) {
 1463                         error = VFS_VGET(mp, dd_ino, LK_SHARED | LK_NOWAIT,
 1464                             &vp1);
 1465                         if (error != 0) {
 1466                                 *wait_ino = dd_ino;
 1467                                 break;
 1468                         }
 1469                 }
 1470                 KASSERT(dd_ino == VTOI(vp1)->i_number,
 1471                     ("directory %ju reparented\n",
 1472                     (uintmax_t)VTOI(vp1)->i_number));
 1473                 if (vp != tvp)
 1474                         vput(vp);
 1475                 vp = vp1;
 1476         }
 1477 
 1478         if (error == ENOTDIR)
 1479                 panic("checkpath: .. not a directory\n");
 1480         if (vp1 != NULL)
 1481                 vput(vp1);
 1482         if (vp != tvp)
 1483                 vput(vp);
 1484         return (error);
 1485 }

Cache object: 79f180198d36b97799107e356579ea74


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