/*-
 * Copyright (c) 1994 The Regents of the University of California.
 * Copyright (c) 1994 Jan-Simon Pendry.
 * Copyright (c) 2005, 2006 Masanori Ozawa <ozawa@ongs.co.jp>, ONGS Inc.
 * Copyright (c) 2006 Daichi Goto <daichi@freebsd.org>
 * 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.
 * 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.
 *
 *      @(#)union.h     8.9 (Berkeley) 12/10/94
 * $FreeBSD: src/sys/fs/unionfs/union.h,v 1.36 2007/10/14 13:55:38 daichi Exp $
 */

#ifndef _MISCFS_UNION_H_
#define _MISCFS_UNION_H_

#define UNIONFS_DEBUG

struct union_args {
        char            *target;        /* Target of loopback  */
        int             mntflags;       /* Options on the mount */
};
#define unionfs_args    union_args

#define UNMNT_ABOVE     0x0001          /* Target appears below mount point */
#define UNMNT_BELOW     0x0002          /* Target appears below mount point */
#define UNMNT_REPLACE   0x0003          /* Target replaces mount point */
#define UNMNT_OPMASK    0x0003

#define UNMNT_BITS "\177\20" \
    "b\00above\0b\01below\0b\02replace\0"

#ifdef _KERNEL

/* copy method of attr from lower to upper */
typedef enum _unionfs_copymode {
        UNIONFS_TRADITIONAL = 0,
        UNIONFS_TRANSPARENT,
        UNIONFS_MASQUERADE
} unionfs_copymode;

/* whiteout policy of upper layer */
typedef enum _unionfs_whitemode {
       UNIONFS_WHITE_ALWAYS = 0,
       UNIONFS_WHITE_WHENNEEDED
} unionfs_whitemode;

struct unionfs_mount {
        struct vnode   *um_lowervp;     /* VREFed once */
        struct vnode   *um_uppervp;     /* VREFed once */
        struct vnode   *um_rootvp;      /* ROOT vnode */
        kmutex_t        um_lock;
        unionfs_copymode um_copymode;
        unionfs_whitemode um_whitemode;
        uid_t           um_uid;
        gid_t           um_gid;
        int             um_op;          /* Operation mode */
        u_short         um_udir;
        u_short         um_ufile;
};

/* unionfs status list */
struct unionfs_node_status {
        LIST_ENTRY(unionfs_node_status) uns_list;       /* Status list */
        pid_t           uns_pid;                /* current process id */
        lwpid_t         uns_lid;                /* current thread id */
        int             uns_node_flag;          /* uns flag */
        int             uns_lower_opencnt;      /* open count of lower */
        int             uns_upper_opencnt;      /* open count of upper */
        int             uns_lower_openmode;     /* open mode of lower */
        int             uns_readdir_status;     /* read status of readdir */
};

/* union node status flags */
#define UNS_OPENL_4_READDIR     0x01    /* open lower layer for readdir */

/* A cache of vnode references */
struct unionfs_node {
        struct vnode   *un_lowervp;             /* lower side vnode */
        struct vnode   *un_uppervp;             /* upper side vnode */
        struct vnode   *un_dvp;                 /* parent unionfs vnode */
        struct vnode   *un_vnode;               /* Back pointer */
        LIST_HEAD(, unionfs_node_status) un_unshead;  /* unionfs status head */
        char           *un_path;                /* path */
        int             un_flag;                /* unionfs node flag */
};

/*
 * unionfs node flags
 * It needs the vnode with exclusive lock, when changing the un_flag variable.
 */
#define UNIONFS_OPENEXTL        0x01    /* openextattr (lower) */
#define UNIONFS_OPENEXTU        0x02    /* openextattr (upper) */

#define MOUNTTOUNIONFSMOUNT(mp) ((struct unionfs_mount *)((mp)->mnt_data))
#define VTOUNIONFS(vp) ((struct unionfs_node *)(vp)->v_data)
#define UNIONFSTOV(xp) ((xp)->un_vnode)

int unionfs_nodeget(struct mount *mp, struct vnode *uppervp, struct vnode *lowervp, struct vnode *dvp, struct vnode **vpp, struct componentname *cnp);
void unionfs_noderem(struct vnode *vp);
void unionfs_get_node_status(struct unionfs_node *unp, struct unionfs_node_status **unspp);
void unionfs_tryrem_node_status(struct unionfs_node *unp, struct unionfs_node_status *unsp);

int unionfs_check_rmdir(struct vnode *vp, kauth_cred_t cred);
int unionfs_copyfile(struct unionfs_node *unp, int docopy, kauth_cred_t cred);
void unionfs_create_uppervattr_core(struct unionfs_mount *ump, struct vattr *lva, struct vattr *uva);
int unionfs_create_uppervattr(struct unionfs_mount *ump, struct vnode *lvp, struct vattr *uva, kauth_cred_t cred);
int unionfs_mkshadowdir(struct unionfs_mount *ump, struct vnode *duvp, struct unionfs_node *unp, struct componentname *cnp);
int unionfs_mkwhiteout(struct vnode *dvp, struct componentname *cnp, const char *path);
int unionfs_relookup_for_create(struct vnode *dvp, struct componentname *cnp);
int unionfs_relookup_for_delete(struct vnode *dvp, struct componentname *cnp);
int unionfs_relookup_for_rename(struct vnode *dvp, struct componentname *cnp);

#ifdef DIAGNOSTIC
struct vnode   *unionfs_checklowervp(struct vnode *vp, const char *fil, int lno);
struct vnode   *unionfs_checkuppervp(struct vnode *vp, const char *fil, int lno);
#define UNIONFSVPTOLOWERVP(vp) unionfs_checklowervp((vp), __FILE__, __LINE__)
#define UNIONFSVPTOUPPERVP(vp) unionfs_checkuppervp((vp), __FILE__, __LINE__)
#else
#define UNIONFSVPTOLOWERVP(vp) (VTOUNIONFS(vp)->un_lowervp)
#define UNIONFSVPTOUPPERVP(vp) (VTOUNIONFS(vp)->un_uppervp)
#endif

extern int (**unionfs_vnodeop_p)(void *);

#ifdef MALLOC_DECLARE
MALLOC_DECLARE(M_UNIONFSPATH);
#endif

#ifdef UNIONFS_DEBUG
#define UNIONFSDEBUG(format, args...) printf(format ,## args)
#else
#define UNIONFSDEBUG(format, args...)
#endif                          /* UNIONFS_DEBUG */

#endif /* _KERNEL */
#endif /* _MISCFS_UNION_H_ */