1 /* 2 * Copyright (c) 1992, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software donated to Berkeley by 6 * Jan-Simon Pendry. 7 * 8 * %sccs.include.redist.c% 9 * 10 * @(#)null.h 8.2 (Berkeley) 01/21/94 11 * 12 * $Id: lofs.h,v 1.8 1992/05/30 10:05:43 jsp Exp jsp $ 13 */ 14 15 struct null_args { 16 char *target; /* Target of loopback */ 17 }; 18 19 struct null_mount { 20 struct mount *nullm_vfs; 21 struct vnode *nullm_rootvp; /* Reference to root null_node */ 22 }; 23 24 #ifdef KERNEL 25 /* 26 * A cache of vnode references 27 */ 28 struct null_node { 29 struct null_node *null_forw; /* Hash chain */ 30 struct null_node *null_back; 31 struct vnode *null_lowervp; /* VREFed once */ 32 struct vnode *null_vnode; /* Back pointer */ 33 }; 34 35 extern int null_node_create __P((struct mount *mp, struct vnode *target, struct vnode **vpp)); 36 37 #define MOUNTTONULLMOUNT(mp) ((struct null_mount *)((mp)->mnt_data)) 38 #define VTONULL(vp) ((struct null_node *)(vp)->v_data) 39 #define NULLTOV(xp) ((xp)->null_vnode) 40 #ifdef NULLFS_DIAGNOSTIC 41 extern struct vnode *null_checkvp __P((struct vnode *vp, char *fil, int lno)); 42 #define NULLVPTOLOWERVP(vp) null_checkvp((vp), __FILE__, __LINE__) 43 #else 44 #define NULLVPTOLOWERVP(vp) (VTONULL(vp)->null_lowervp) 45 #endif 46 47 extern int (**null_vnodeop_p)(); 48 extern struct vfsops null_vfsops; 49 #endif /* KERNEL */ 50