示例#1
0
/*
 * Returns non-zero if we need to lock the namecache element
 * exclusively.  Unless otherwise requested by NLC_SHAREDLOCK,
 * the last element of the namecache lookup will be locked
 * exclusively.
 *
 * NOTE: Even if we return on-zero, an unresolved namecache record
 *	 will always be locked exclusively.
 */
static __inline
int
wantsexcllock(struct nlookupdata *nd, const char *ptr)
{
	if ((nd->nl_flags & NLC_SHAREDLOCK) == 0)
		return(islastelement(ptr));
	return(0);
}
示例#2
0
文件: quicksort.c 项目: Rubusch/c
/*
  sorting

  calls the recursive function
//*/
void sort(void** first)
{
  // checks
  if(NULL == first) return;
  if(isfirstelement(*first) && islastelement(*first)) return;

  // inits
  void* first_elem = *first;
  void* last_elem = first_elem;
  while( !islastelement(last_elem)){
    last_elem = getnextelement(last_elem);
  }

  // actual sort (recursive)
  quicksort(first_elem, last_elem);

  // reset *first to the new first;
  while(!isfirstelement(first_elem)){
    first_elem = getprevelement(first_elem);
  }
  *first = first_elem;
}
示例#3
0
文件: bubblesort.c 项目: Rubusch/c
/*
  iterates to the following element
//*/
void* iterate(void* arg, void** first)
{
  element_t* tmp = (element_t*) arg;
  
  // check for first element and set first
  if(isfirstelement(tmp)){
    *first = tmp;
  }

  // return the following element
  if(islastelement(tmp)){
    return *first;
  }else{
    return getnextelement(tmp);
  }
}
示例#4
0
文件: bubblesort.c 项目: Rubusch/c
/*
  sorting function - this function should work completely abstracted from the data type to sort
//*/
void* sort(void** first)
{
  void* tmp = *first;

  char done = 0;

  while(!done){
    done = 1;
    tmp = *first;

    // while there is a next compare "tmp" and "tmp->next", in case swap
    while(!islastelement(tmp)){
      if(compare(tmp, getnextelement(tmp))){
	swap((void*) &tmp, getnextelement(tmp));
	done = 0;
      }

      tmp = iterate(tmp, first);
    }
  }

  return NULL;
}
示例#5
0
文件: quicksort.c 项目: Rubusch/c
/*
  part of the recursive approach of a quicksort implementation

  iterate thru bottom half and push higher elements to upper half (before pivot) - multithreading possible
//*/
void quicksort(void* first, void* last)
{
  // checks
  if(NULL == first) return;
  if(NULL == last) return;
  if(isfirstelement(last)) return;
  if(islastelement(first)) return;
  if(first == last) return;

  // ok, init
  void* smaller = first;
  void* pivot = last;
  void* greater = getprevelement(pivot);
  if(smaller == greater) return;

  // freeze the pointers to the position
  int freeze_greater = 0;
  int freeze_smaller = 0;

  while(1){
    if(!freeze_smaller){
      // compare: pivot < smaller
      if(0 < compare(smaller, pivot)){
	// freeze
	freeze_smaller = 1;

      }else{
	smaller = getnextelement(smaller);
      }
    }

    if(!freeze_greater){
      // compare: pivot > greater
      if(0 < compare(pivot, greater)){
	// freeze
	freeze_greater = 1;

      }else{
	greater = getprevelement(greater);
      }
    }

    // break out
    if(smaller == greater) break;
    if(smaller == getnextelement(greater)) break;
    if(greater == getprevelement(smaller)) break;

    // both are frozen - interchange
    if(freeze_smaller && freeze_greater){
      if(smaller == first) first = greater; // set new first
      if(0 > interchange(&smaller, &greater)){
	perror("something in the queue was NULL?!"); // this is impossible if the implementation is ok!
	return;
      }

      smaller = getnextelement(smaller);
      greater = getprevelement(greater);
      freeze_smaller = 0; 
      freeze_greater = 0;
    }
  }

  // swap pivot with smaller
  if(freeze_greater && (0 > compare(pivot, greater))){
    if(0 > interchange(&pivot, &greater)) return;    
    last = pivot; // set the new last
    pivot = greater; // set the new pivot
  }else{
    if(0 == compare(smaller, pivot)){
      smaller = getnextelement(smaller);
    }
    if(smaller == first) first = pivot; // set the new pivot
    if(0 > interchange(&smaller, &pivot)) return;
    last = pivot; // set the new last
    pivot = smaller; // set the new pivot
  }

  // split into:  first - (pivot-1) and pivot - last
  // everything already ordered
  if(pivot == last) return;

  // call for lower half
  quicksort(first, getprevelement(pivot));

  // call for upper half
  quicksort(pivot, last);
}
示例#6
0
/*
 * Do a generic nlookup.  Note that the passed nd is not nlookup_done()'d
 * on return, even if an error occurs.  If no error occurs or NLC_CREATE
 * is flagged and ENOENT is returned, then the returned nl_nch is always
 * referenced and locked exclusively.
 *
 * WARNING: For any general error other than ENOENT w/NLC_CREATE, the
 *	    the resulting nl_nch may or may not be locked and if locked
 *	    might be locked either shared or exclusive.
 *
 * Intermediate directory elements, including the current directory, require
 * execute (search) permission.  nlookup does not examine the access 
 * permissions on the returned element.
 *
 * If NLC_CREATE is set the last directory must allow node creation,
 * and an error code of 0 will be returned for a non-existant
 * target (not ENOENT).
 *
 * If NLC_RENAME_DST is set the last directory mut allow node deletion,
 * plus the sticky check is made, and an error code of 0 will be returned
 * for a non-existant target (not ENOENT).
 *
 * If NLC_DELETE is set the last directory mut allow node deletion,
 * plus the sticky check is made.
 *
 * If NLC_REFDVP is set nd->nl_dvp will be set to the directory vnode
 * of the returned entry.  The vnode will be referenced, but not locked,
 * and will be released by nlookup_done() along with everything else.
 *
 * NOTE: As an optimization we attempt to obtain a shared namecache lock
 *	 on any intermediate elements.  On success, the returned element
 *	 is ALWAYS locked exclusively.
 */
int
nlookup(struct nlookupdata *nd)
{
    globaldata_t gd = mycpu;
    struct nlcomponent nlc;
    struct nchandle nch;
    struct nchandle par;
    struct nchandle nctmp;
    struct mount *mp;
    struct vnode *hvp;		/* hold to prevent recyclement */
    int wasdotordotdot;
    char *ptr;
    char *nptr;
    int error;
    int len;
    int dflags;
    int hit = 1;
    int saveflag = nd->nl_flags & ~NLC_NCDIR;
    boolean_t doretry = FALSE;
    boolean_t inretry = FALSE;

nlookup_start:
#ifdef KTRACE
    if (KTRPOINT(nd->nl_td, KTR_NAMEI))
	ktrnamei(nd->nl_td->td_lwp, nd->nl_path);
#endif
    bzero(&nlc, sizeof(nlc));

    /*
     * Setup for the loop.  The current working namecache element is
     * always at least referenced.  We lock it as required, but always
     * return a locked, resolved namecache entry.
     */
    nd->nl_loopcnt = 0;
    if (nd->nl_dvp) {
	vrele(nd->nl_dvp);
	nd->nl_dvp = NULL;
    }
    ptr = nd->nl_path;

    /*
     * Loop on the path components.  At the top of the loop nd->nl_nch
     * is ref'd and unlocked and represents our current position.
     */
    for (;;) {
	/*
	 * Make sure nl_nch is locked so we can access the vnode, resolution
	 * state, etc.
	 */
	if ((nd->nl_flags & NLC_NCPISLOCKED) == 0) {
		nd->nl_flags |= NLC_NCPISLOCKED;
		cache_lock_maybe_shared(&nd->nl_nch, wantsexcllock(nd, ptr));
	}

	/*
	 * Check if the root directory should replace the current
	 * directory.  This is done at the start of a translation
	 * or after a symbolic link has been found.  In other cases
	 * ptr will never be pointing at a '/'.
	 */
	if (*ptr == '/') {
	    do {
		++ptr;
	    } while (*ptr == '/');
	    cache_unlock(&nd->nl_nch);
	    cache_get_maybe_shared(&nd->nl_rootnch, &nch,
				   wantsexcllock(nd, ptr));
	    if (nd->nl_flags & NLC_NCDIR) {
		    cache_drop_ncdir(&nd->nl_nch);
		    nd->nl_flags &= ~NLC_NCDIR;
	    } else {
		    cache_drop(&nd->nl_nch);
	    }
	    nd->nl_nch = nch;		/* remains locked */

	    /*
	     * Fast-track termination.  There is no parent directory of
	     * the root in the same mount from the point of view of
	     * the caller so return EACCES if NLC_REFDVP is specified,
	     * and EEXIST if NLC_CREATE is also specified.
	     * e.g. 'rmdir /' or 'mkdir /' are not allowed.
	     */
	    if (*ptr == 0) {
		if (nd->nl_flags & NLC_REFDVP)
			error = (nd->nl_flags & NLC_CREATE) ? EEXIST : EACCES;
		else
			error = 0;
		break;
	    }
	    continue;
	}

	/*
	 * Pre-calculate next path component so we can check whether the
	 * current component directory is the last directory in the path
	 * or not.
	 */
	for (nptr = ptr; *nptr && *nptr != '/'; ++nptr)
		;

	/*
	 * Check directory search permissions (nd->nl_nch is locked & refd).
	 * This will load dflags to obtain directory-special permissions to
	 * be checked along with the last component.
	 *
	 * We only need to pass-in &dflags for the second-to-last component.
	 * Optimize by passing-in NULL for any prior components, which may
	 * allow the code to bypass the naccess() call.
	 */
	dflags = 0;
	if (*nptr == '/')
	    error = naccess(&nd->nl_nch, NLC_EXEC, nd->nl_cred, NULL);
	else
	    error = naccess(&nd->nl_nch, NLC_EXEC, nd->nl_cred, &dflags);
	if (error) {
	    if (keeperror(nd, error))
		    break;
	    error = 0;
	}

	/*
	 * Extract the next (or last) path component.  Path components are
	 * limited to 255 characters.
	 */
	nlc.nlc_nameptr = ptr;
	nlc.nlc_namelen = nptr - ptr;
	ptr = nptr;
	if (nlc.nlc_namelen >= 256) {
	    error = ENAMETOOLONG;
	    break;
	}

	/*
	 * Lookup the path component in the cache, creating an unresolved
	 * entry if necessary.  We have to handle "." and ".." as special
	 * cases.
	 *
	 * When handling ".." we have to detect a traversal back through a
	 * mount point.   If we are at the root, ".." just returns the root.
	 *
	 * When handling "." or ".." we also have to recalculate dflags
	 * since our dflags will be for some sub-directory instead of the
	 * parent dir.
	 *
	 * This subsection returns a locked, refd 'nch' unless it errors out,
	 * and an unlocked but still ref'd nd->nl_nch.
	 *
	 * The namecache topology is not allowed to be disconnected, so 
	 * encountering a NULL parent will generate EINVAL.  This typically
	 * occurs when a directory is removed out from under a process.
	 *
	 * WARNING! The unlocking of nd->nl_nch is sensitive code.
	 */
	KKASSERT(nd->nl_flags & NLC_NCPISLOCKED);

	if (nlc.nlc_namelen == 1 && nlc.nlc_nameptr[0] == '.') {
	    cache_unlock(&nd->nl_nch);
	    nd->nl_flags &= ~NLC_NCPISLOCKED;
	    cache_get_maybe_shared(&nd->nl_nch, &nch, wantsexcllock(nd, ptr));
	    wasdotordotdot = 1;
	} else if (nlc.nlc_namelen == 2 && 
		   nlc.nlc_nameptr[0] == '.' && nlc.nlc_nameptr[1] == '.') {
	    if (nd->nl_nch.mount == nd->nl_rootnch.mount &&
		nd->nl_nch.ncp == nd->nl_rootnch.ncp
	    ) {
		/*
		 * ".." at the root returns the root
		 */
		cache_unlock(&nd->nl_nch);
		nd->nl_flags &= ~NLC_NCPISLOCKED;
		cache_get_maybe_shared(&nd->nl_nch, &nch,
				       wantsexcllock(nd, ptr));
	    } else {
		/*
		 * Locate the parent ncp.  If we are at the root of a
		 * filesystem mount we have to skip to the mounted-on
		 * point in the underlying filesystem.
		 *
		 * Expect the parent to always be good since the
		 * mountpoint doesn't go away.  XXX hack.  cache_get()
		 * requires the ncp to already have a ref as a safety.
		 *
		 * However, a process which has been broken out of a chroot
		 * will wind up with a NULL parent if it tries to '..' above
		 * the real root, deal with the case.  Note that this does
		 * not protect us from a jail breakout, it just stops a panic
		 * if the jail-broken process tries to '..' past the real
		 * root.
		 */
		nctmp = nd->nl_nch;
		while (nctmp.ncp == nctmp.mount->mnt_ncmountpt.ncp) {
			nctmp = nctmp.mount->mnt_ncmounton;
			if (nctmp.ncp == NULL)
				break;
		}
		if (nctmp.ncp == NULL) {
			if (curthread->td_proc) {
				kprintf("vfs_nlookup: '..' traverse broke "
					"jail: pid %d (%s)\n",
					curthread->td_proc->p_pid,
					curthread->td_comm);
			}
			nctmp = nd->nl_rootnch;
		} else {
			nctmp.ncp = nctmp.ncp->nc_parent;
		}
		cache_hold(&nctmp);
		cache_unlock(&nd->nl_nch);
		nd->nl_flags &= ~NLC_NCPISLOCKED;
		cache_get_maybe_shared(&nctmp, &nch, wantsexcllock(nd, ptr));
		cache_drop(&nctmp);		/* NOTE: zero's nctmp */
	    }
	    wasdotordotdot = 2;
	} else {
	    /*
	     * Must unlock nl_nch when traversing down the path.  However,
	     * the child ncp has not yet been found/created and the parent's
	     * child list might be empty.  Thus releasing the lock can
	     * allow a race whereby the parent ncp's vnode is recycled.
	     * This case can occur especially when maxvnodes is set very low.
	     *
	     * We need the parent's ncp to remain resolved for all normal
	     * filesystem activities, so we vhold() the vp during the lookup
	     * to prevent recyclement due to vnlru / maxvnodes.
	     *
	     * If we race an unlink or rename the ncp might be marked
	     * DESTROYED after resolution, requiring a retry.
	     */
	    if ((hvp = nd->nl_nch.ncp->nc_vp) != NULL)
		vhold(hvp);
	    cache_unlock(&nd->nl_nch);
	    nd->nl_flags &= ~NLC_NCPISLOCKED;
	    error = cache_nlookup_maybe_shared(&nd->nl_nch, &nlc,
					       wantsexcllock(nd, ptr), &nch);
	    if (error == EWOULDBLOCK) {
		    nch = cache_nlookup(&nd->nl_nch, &nlc);
		    if (nch.ncp->nc_flag & NCF_UNRESOLVED)
			hit = 0;
		    for (;;) {
			error = cache_resolve(&nch, nd->nl_cred);
			if (error != EAGAIN &&
			    (nch.ncp->nc_flag & NCF_DESTROYED) == 0) {
				if (error == ESTALE) {
				    if (!inretry)
					error = ENOENT;
				    doretry = TRUE;
				}
				break;
			}
			kprintf("[diagnostic] nlookup: relookup %*.*s\n",
				nch.ncp->nc_nlen, nch.ncp->nc_nlen,
				nch.ncp->nc_name);
			cache_put(&nch);
			nch = cache_nlookup(&nd->nl_nch, &nlc);
		    }
	    }
	    if (hvp)
		vdrop(hvp);
	    wasdotordotdot = 0;
	}

	/*
	 * If the last component was "." or ".." our dflags no longer
	 * represents the parent directory and we have to explicitly
	 * look it up.
	 *
	 * Expect the parent to be good since nch is locked.
	 */
	if (wasdotordotdot && error == 0) {
	    dflags = 0;
	    if ((par.ncp = nch.ncp->nc_parent) != NULL) {
		par.mount = nch.mount;
		cache_hold(&par);
		cache_lock_maybe_shared(&par, wantsexcllock(nd, ptr));
		error = naccess(&par, 0, nd->nl_cred, &dflags);
		cache_put(&par);
		if (error) {
		    if (!keeperror(nd, error))
			    error = 0;
		}
	    }
	}

	/*
	 * [end of subsection]
	 *
	 * nch is locked and referenced.
	 * nd->nl_nch is unlocked and referenced.
	 *
	 * nl_nch must be unlocked or we could chain lock to the root
	 * if a resolve gets stuck (e.g. in NFS).
	 */
	KKASSERT((nd->nl_flags & NLC_NCPISLOCKED) == 0);

	/*
	 * Resolve the namespace if necessary.  The ncp returned by
	 * cache_nlookup() is referenced and locked.
	 *
	 * XXX neither '.' nor '..' should return EAGAIN since they were
	 * previously resolved and thus cannot be newly created ncp's.
	 */
	if (nch.ncp->nc_flag & NCF_UNRESOLVED) {
	    hit = 0;
	    error = cache_resolve(&nch, nd->nl_cred);
	    if (error == ESTALE) {
		if (!inretry)
		    error = ENOENT;
		doretry = TRUE;
	    }
	    KKASSERT(error != EAGAIN);
	} else {
	    error = nch.ncp->nc_error;
	}

	/*
	 * Early completion.  ENOENT is not an error if this is the last
	 * component and NLC_CREATE or NLC_RENAME (rename target) was
	 * requested.  Note that ncp->nc_error is left as ENOENT in that
	 * case, which we check later on.
	 *
	 * Also handle invalid '.' or '..' components terminating a path
	 * for a create/rename/delete.  The standard requires this and pax
	 * pretty stupidly depends on it.
	 */
	if (islastelement(ptr)) {
	    if (error == ENOENT &&
		(nd->nl_flags & (NLC_CREATE | NLC_RENAME_DST))
	    ) {
		if (nd->nl_flags & NLC_NFS_RDONLY) {
			error = EROFS;
		} else {
			error = naccess(&nch, nd->nl_flags | dflags,
					nd->nl_cred, NULL);
		}
	    }
	    if (error == 0 && wasdotordotdot &&
		(nd->nl_flags & (NLC_CREATE | NLC_DELETE |
				 NLC_RENAME_SRC | NLC_RENAME_DST))) {
		/*
		 * POSIX junk
		 */
		if (nd->nl_flags & NLC_CREATE)
			error = EEXIST;
		else if (nd->nl_flags & NLC_DELETE)
			error = (wasdotordotdot == 1) ? EINVAL : ENOTEMPTY;
		else
			error = EINVAL;
	    }
	}

	/*
	 * Early completion on error.
	 */
	if (error) {
	    cache_put(&nch);
	    break;
	}

	/*
	 * If the element is a symlink and it is either not the last
	 * element or it is the last element and we are allowed to
	 * follow symlinks, resolve the symlink.
	 */
	if ((nch.ncp->nc_flag & NCF_ISSYMLINK) &&
	    (*ptr || (nd->nl_flags & NLC_FOLLOW))
	) {
	    if (nd->nl_loopcnt++ >= MAXSYMLINKS) {
		error = ELOOP;
		cache_put(&nch);
		break;
	    }
	    error = nreadsymlink(nd, &nch, &nlc);
	    cache_put(&nch);
	    if (error)
		break;

	    /*
	     * Concatenate trailing path elements onto the returned symlink.
	     * Note that if the path component (ptr) is not exhausted, it
	     * will being with a '/', so we do not have to add another one.
	     *
	     * The symlink may not be empty.
	     */
	    len = strlen(ptr);
	    if (nlc.nlc_namelen == 0 || nlc.nlc_namelen + len >= MAXPATHLEN) {
		error = nlc.nlc_namelen ? ENAMETOOLONG : ENOENT;
		objcache_put(namei_oc, nlc.nlc_nameptr);
		break;
	    }
	    bcopy(ptr, nlc.nlc_nameptr + nlc.nlc_namelen, len + 1);
	    if (nd->nl_flags & NLC_HASBUF)
		objcache_put(namei_oc, nd->nl_path);
	    nd->nl_path = nlc.nlc_nameptr;
	    nd->nl_flags |= NLC_HASBUF;
	    ptr = nd->nl_path;

	    /*
	     * Go back up to the top to resolve any initial '/'s in the
	     * symlink.
	     */
	    continue;
	}
	
	/*
	 * If the element is a directory and we are crossing a mount point,
	 * Locate the mount.
	 */
	while ((nch.ncp->nc_flag & NCF_ISMOUNTPT) && 
	    (nd->nl_flags & NLC_NOCROSSMOUNT) == 0 &&
	    (mp = cache_findmount(&nch)) != NULL
	) {
	    struct vnode *tdp;
	    int vfs_do_busy = 0;

	    /*
	     * VFS must be busied before the namecache entry is locked,
	     * but we don't want to waste time calling vfs_busy() if the
	     * mount point is already resolved.
	     */
again:
	    cache_put(&nch);
	    if (vfs_do_busy) {
		while (vfs_busy(mp, 0)) {
		    if (mp->mnt_kern_flag & MNTK_UNMOUNT) {
			kprintf("nlookup: warning umount race avoided\n");
			cache_dropmount(mp);
			error = EBUSY;
			vfs_do_busy = 0;
			goto double_break;
		    }
		}
	    }
	    cache_get_maybe_shared(&mp->mnt_ncmountpt, &nch,
				   wantsexcllock(nd, ptr));

	    if (nch.ncp->nc_flag & NCF_UNRESOLVED) {
		if (vfs_do_busy == 0) {
		    vfs_do_busy = 1;
		    goto again;
		}
		error = VFS_ROOT(mp, &tdp);
		vfs_unbusy(mp);
		vfs_do_busy = 0;
		if (keeperror(nd, error)) {
		    cache_dropmount(mp);
		    break;
		}
		if (error == 0) {
		    cache_setvp(&nch, tdp);
		    vput(tdp);
		}
	    }
	    if (vfs_do_busy)
		vfs_unbusy(mp);
	    cache_dropmount(mp);
	}

	if (keeperror(nd, error)) {
	    cache_put(&nch);
double_break:
	    break;
	}
	    
	/*
	 * Skip any slashes to get to the next element.  If there 
	 * are any slashes at all the current element must be a
	 * directory or, in the create case, intended to become a directory.
	 * If it isn't we break without incrementing ptr and fall through
	 * to the failure case below.
	 */
	while (*ptr == '/') {
	    if ((nch.ncp->nc_flag & NCF_ISDIR) == 0 && 
		!(nd->nl_flags & NLC_WILLBEDIR)
	    ) {
		break;
	    }
	    ++ptr;
	}

	/*
	 * Continuation case: additional elements and the current
	 * element is a directory.
	 */
	if (*ptr && (nch.ncp->nc_flag & NCF_ISDIR)) {
	    if (nd->nl_flags & NLC_NCDIR) {
		    cache_drop_ncdir(&nd->nl_nch);
		    nd->nl_flags &= ~NLC_NCDIR;
	    } else {
		    cache_drop(&nd->nl_nch);
	    }
	    cache_unlock(&nch);
	    KKASSERT((nd->nl_flags & NLC_NCPISLOCKED) == 0);
	    nd->nl_nch = nch;
	    continue;
	}

	/*
	 * Failure case: additional elements and the current element
	 * is not a directory
	 */
	if (*ptr) {
	    cache_put(&nch);
	    error = ENOTDIR;
	    break;
	}

	/*
	 * Successful lookup of last element.
	 *
	 * Check permissions if the target exists.  If the target does not
	 * exist directory permissions were already tested in the early
	 * completion code above.
	 *
	 * nd->nl_flags will be adjusted on return with NLC_APPENDONLY
	 * if the file is marked append-only, and NLC_STICKY if the directory
	 * containing the file is sticky.
	 */
	if (nch.ncp->nc_vp && (nd->nl_flags & NLC_ALLCHKS)) {
	    error = naccess(&nch, nd->nl_flags | dflags,
			    nd->nl_cred, NULL);
	    if (keeperror(nd, error)) {
		cache_put(&nch);
		break;
	    }
	}

	/*
	 * Termination: no more elements.
	 *
	 * If NLC_REFDVP is set acquire a referenced parent dvp.
	 */
	if (nd->nl_flags & NLC_REFDVP) {
		cache_lock(&nd->nl_nch);
		error = cache_vref(&nd->nl_nch, nd->nl_cred, &nd->nl_dvp);
		cache_unlock(&nd->nl_nch);
		if (keeperror(nd, error)) {
			kprintf("NLC_REFDVP: Cannot ref dvp of %p\n", nch.ncp);
			cache_put(&nch);
			break;
		}
	}
	if (nd->nl_flags & NLC_NCDIR) {
		cache_drop_ncdir(&nd->nl_nch);
		nd->nl_flags &= ~NLC_NCDIR;
	} else {
		cache_drop(&nd->nl_nch);
	}
	nd->nl_nch = nch;
	nd->nl_flags |= NLC_NCPISLOCKED;
	error = 0;
	break;
    }

    if (hit)
	++gd->gd_nchstats->ncs_longhits;
    else
	++gd->gd_nchstats->ncs_longmiss;

    if (nd->nl_flags & NLC_NCPISLOCKED)
	KKASSERT(cache_lockstatus(&nd->nl_nch) > 0);

    /*
     * Retry the whole thing if doretry flag is set, but only once.
     * autofs(5) may mount another filesystem under its root directory
     * while resolving a path.
     */
    if (doretry && !inretry) {
	inretry = TRUE;
	nd->nl_flags &= NLC_NCDIR;
	nd->nl_flags |= saveflag;
	goto nlookup_start;
    }

    /*
     * NOTE: If NLC_CREATE was set the ncp may represent a negative hit
     * (ncp->nc_error will be ENOENT), but we will still return an error
     * code of 0.
     */
    return(error);
}