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/* Hurd unionfs
Copyright (C) 2001, 2002 Free Software Foundation, Inc.
Written by Moritz Schulte <moritz@duesseldorf.ccc.de>.
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the
License, or * (at your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
USA. */
/* This unionfs knows about two different kind of nodes: `light nodes'
(in short: lnode) and `nodes' (or: netfs nodes) as used by
libnetfs. They have different tasks and therefore this division
makes sense.
lnodes form the filesystem tree as seen by the user; most
importantly they contain the `name' of the node.
lnodes are small and cheap, they are not cached (nodes are).
lnodes are usually created when a node is looked up and destroyed
when that node gets destroyed; but there are also reasons for
lnodes _not_ being destroyed.
The distinction makes it possible to keep certain information for
the unionfs in these lnodes while netfs nodes don't have to stay in
memory.
lnodes have to be looked up first before a node is looked up. Each
lnode contains a pointer to the netfs node, which might be NULL in
case the netfs node is not in memory anymore. */
/* General information and properties for the unionfs. */
#ifndef INCLUDED_UNIONFS_H
#define INCLUDED_UNIONFS_H
#include <hurd/netfs.h>
#include <sys/types.h>
#include "node.h"
#include "lib.h"
/* Default maximum number of nodes in the cache. */
#define NCACHE_SIZE 256
/* The inode for the root node. */
#define UNIONFS_ROOT_INODE 1
/* Flags for UNIONFS_FLAGS. */
/* Print debugging messages to stderr. */
#define FLAG_UNIONFS_MODE_DEBUG 0x00000001
/* Use copy-on-write. */
#define FLAG_UNIONFS_MODE_COW 0x00000002
/* Flags describing certain properties of the unionfs. */
extern int unionfs_flags;
/* The filesystem id (the pid). */
extern pid_t fsid;
/* Mapped time, used for updating node information. */
extern volatile struct mapped_time_value *maptime;
/* A port to the underlying node. */
extern mach_port_t underlying_node;
/* stat information for the underlying node. */
extern io_statbuf_t underlying_node_stat;
/* Send a debugging message, if unionfs is in debugging mode. */
#define debug_msg(fmt, args...) \
do \
{ \
if (unionfs_flags & FLAG_UNIONFS_MODE_DEBUG) \
debug_msg_send (fmt , ## args); \
} \
while (0)
#endif
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