NetBSD-5.0.2/sys/miscfs/genfs/layer.h
/* $NetBSD: layer.h,v 1.13 2008/01/30 09:50:23 ad Exp $ */
/*
* Copyright (c) 1999 National Aeronautics & Space Administration
* All rights reserved.
*
* This software was written by William Studenmund of the
* Numerical Aerospace Simulation 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 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. 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
*/
#ifndef _MISCFS_GENFS_LAYER_H_
#define _MISCFS_GENFS_LAYER_H_
struct layer_args {
char *target; /* Target of loopback */
struct export_args30 _pad1; /* compat with old userland tools */
};
#ifdef _KERNEL
struct layer_node;
LIST_HEAD(layer_node_hashhead, layer_node);
struct layer_mount {
struct mount *layerm_vfs;
struct vnode *layerm_rootvp; /* Ref to root layer_node */
u_int layerm_flags; /* mount point layer flags */
u_int layerm_size; /* size of fs's struct node */
enum vtype layerm_tag; /* vtag of our vnodes */
int /* bypass routine for this mount */
(*layerm_bypass)(void *);
int (*layerm_alloc) /* alloc a new layer node */
(struct mount *, struct vnode *,
struct vnode **);
int (**layerm_vnodeop_p) /* ops for our nodes */
(void *);
struct layer_node_hashhead /* head of hash list for layer_nodes */
*layerm_node_hashtbl;
u_long layerm_node_hash; /* hash mask for hash chain */
kmutex_t layerm_hashlock; /* interlock for hash chain. */
};
#define LAYERFS_MFLAGS 0x00000fff /* reserved layer mount flags */
#define LAYERFS_MBYPASSDEBUG 0x00000001
/*
* A cache of vnode references
*/
struct layer_node {
LIST_ENTRY(layer_node) layer_hash; /* Hash list */
struct vnode *layer_lowervp; /* VREFed once */
struct vnode *layer_vnode; /* Back pointer */
unsigned int layer_flags; /* locking, etc. */
};
#define LAYERFS_RESFLAGS 0x00000fff /* flags reserved for layerfs */
#define LAYERFS_REMOVED 0x00000001 /* Did a remove on this node */
/*
* The following macros handle upperfs-specific locking. They are needed
* when the lowerfs does not export a struct lock for locking use by the
* upper layers. These macros are inteded for adjusting the upperfs
* struct lock to reflect changes in the underlying vnode's lock state.
*/
#define LAYERFS_UPPERLOCK(v, f, r) do { \
if ((v)->v_vnlock == NULL) \
r = vlockmgr(&(v)->v_lock, (f)); \
else \
r = 0; \
} while (0)
#define LAYERFS_UPPERUNLOCK(v, f, r) do { \
if ((v)->v_vnlock == NULL) \
r = vlockmgr(&(v)->v_lock, (f) | LK_RELEASE); \
else \
r = 0; \
} while (0)
#define LAYERFS_UPPERISLOCKED(v, r) do { \
if ((v)->v_vnlock == NULL) \
r = vlockstatus(&(v)->v_lock); \
else \
r = -1; \
} while (0)
#define LAYERFS_DO_BYPASS(vp, ap) \
(*MOUNTTOLAYERMOUNT((vp)->v_mount)->layerm_bypass)((ap))
struct vnode *layer_checkvp(struct vnode *vp, const char *fil, int lno);
#define MOUNTTOLAYERMOUNT(mp) ((struct layer_mount *)((mp)->mnt_data))
#define VTOLAYER(vp) ((struct layer_node *)(vp)->v_data)
#define LAYERTOV(xp) ((xp)->layer_vnode)
#ifdef LAYERFS_DIAGNOSTIC
#define LAYERVPTOLOWERVP(vp) layer_checkvp((vp), __FILE__, __LINE__)
extern int layerfs_debug;
#else
#define LAYERVPTOLOWERVP(vp) (VTOLAYER(vp)->layer_lowervp)
#endif
#endif /* _KERNEL */
#endif /* _MISCFS_GENFS_LAYER_H_ */