NetBSD/sys/miscfs/overlay/overlay.h
wrstuden fab192f2d2 Add overlay, a layered file system which overlays itself on
the underlying fs, rather than exporting it to another part of the
directory name space.
2000-01-20 19:06:13 +00:00

131 lines
5.5 KiB
C

/* $NetBSD: overlay.h,v 1.1 2000/01/20 19:06:15 wrstuden Exp $ */
/*
* Copyright (c) 1999 National Aeronautics & Space Administration
* All rights reserved.
*
* This software was written by William Studnemund of the
* Numerical Aerospace Similation Facility, NASA Ames Research Center.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the the name of the National Aeronautics & Space Administration
* nor the names of its contributors may be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE NATIONAL AERONAUTICS & SPACE ADMINISTRATION
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE ADMINISTRATION OR CONTRIB-
* UTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
* OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Copyright (c) 1992, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software donated to Berkeley by
* Jan-Simon Pendry.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from: Id: lofs.h,v 1.8 1992/05/30 10:05:43 jsp Exp
* @(#)null.h 8.2 (Berkeley) 1/21/94
*/
#include <miscfs/genfs/layer.h>
struct overlay_args {
struct layer_args la; /* generic layerfs args */
};
/*
* We leave ova_target for two reasons. One, We can tell the difference
* between a mount_overlay -u and a call from mountd as the former will
* pass a pointer to a string while the latter will pass NULL. Two,
* filesystems based on the overlay layer might have use for it.
*/
#define ova_target la.target
#define ova_export la.export
#ifdef _KERNEL
struct overlay_mount {
struct layer_mount lm; /* generic layerfs mount stuff */
};
#define ovm_vfs lm.layerm_vfs
#define ovm_rootvp lm.layerm_rootvp
#define ovm_export lm.layerm_export
#define ovm_flags lm.layerm_flags
#define ovm_size lm.layerm_size
#define ovm_tag lm.layerm_tag
#define ovm_bypass lm.layerm_bypass
#define ovm_alloc lm.layerm_alloc
#define ovm_vnodeop_p lm.layerm_vnodeop_p
#define ovm_node_hashtbl lm.layerm_node_hashtbl
#define ovm_node_hash lm.layerm_node_hash
#define ovm_hashlock lm.layerm_hashlock
/*
* A cache of vnode references
*/
struct overlay_node {
struct layer_node ln;
};
#define ov_hash ln.layer_hash
#define ov_lowervp ln.layer_lowervp
#define ov_vnode ln.layer_vnode
#define ov_flags ln.layer_flags
#define MOUNTTOOVERLAYMOUNT(mp) ((struct overlay_mount *)((mp)->mnt_data))
#define VTOOVERLAY(vp) ((struct overlay_node *)(vp)->v_data)
#define OVERLAYTOV(xp) ((xp)->ov_vnode)
#ifdef OVERLAYFS_DIAGNOSTIC
extern struct vnode *layer_checkvp __P((struct vnode *vp, char *fil, int lno));
#define OVERLAYVPTOLOWERVP(vp) layer_checkvp((vp), __FILE__, __LINE__)
#else
#define OVERLAYVPTOLOWERVP(vp) (VTOOVERLAY(vp)->ov_lowervp)
#endif
extern int (**overlay_vnodeop_p) __P((void *));
extern struct vfsops overlay_vfsops;
#endif /* _KERNEL */