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null.h revision 1.4 
      1 /*	$NetBSD: null.h,v 1.4 1995/03/29 22:08:24 briggs Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1992, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This code is derived from software donated to Berkeley by
      8  * Jan-Simon Pendry.
      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  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *	This product includes software developed by the University of
     21  *	California, Berkeley and its contributors.
     22  * 4. Neither the name of the University nor the names of its contributors
     23  *    may be used to endorse or promote products derived from this software
     24  *    without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     36  * SUCH DAMAGE.
     37  *
     38  *	from: Id: lofs.h,v 1.8 1992/05/30 10:05:43 jsp Exp
     39  *	@(#)null.h	8.2 (Berkeley) 1/21/94
     40  */
     41 
     42 struct null_args {
     43 	char		*target;	/* Target of loopback  */
     44 };
     45 
     46 struct null_mount {
     47 	struct mount	*nullm_vfs;
     48 	struct vnode	*nullm_rootvp;	/* Reference to root null_node */
     49 };
     50 
     51 #ifdef _KERNEL
     52 /*
     53  * A cache of vnode references
     54  */
     55 struct null_node {
     56 	LIST_ENTRY(null_node)	null_hash;	/* Hash list */
     57 	struct vnode	        *null_lowervp;	/* VREFed once */
     58 	struct vnode		*null_vnode;	/* Back pointer */
     59 };
     60 
     61 extern int null_node_create __P((struct mount *mp, struct vnode *target, struct vnode **vpp));
     62 
     63 #define	MOUNTTONULLMOUNT(mp) ((struct null_mount *)((mp)->mnt_data))
     64 #define	VTONULL(vp) ((struct null_node *)(vp)->v_data)
     65 #define	NULLTOV(xp) ((xp)->null_vnode)
     66 #ifdef NULLFS_DIAGNOSTIC
     67 extern struct vnode *null_checkvp __P((struct vnode *vp, char *fil, int lno));
     68 #define	NULLVPTOLOWERVP(vp) null_checkvp((vp), __FILE__, __LINE__)
     69 #else
     70 #define	NULLVPTOLOWERVP(vp) (VTONULL(vp)->null_lowervp)
     71 #endif
     72 
     73 extern int (**null_vnodeop_p)();
     74 extern struct vfsops null_vfsops;
     75 #endif /* _KERNEL */
     76