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union.h revision 1.9
      1 /*	$NetBSD: union.h,v 1.9 2003/10/03 16:34:31 yamt Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1994 The Regents of the University of California.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software donated to Berkeley by
      8  * Jan-Simon Pendry.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. Neither the name of the University nor the names of its contributors
     19  *    may be used to endorse or promote products derived from this software
     20  *    without specific prior written permission.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     32  * SUCH DAMAGE.
     33  *
     34  *	@(#)union.h	8.9 (Berkeley) 12/10/94
     35  */
     36 
     37 /*
     38  * Copyright (c) 1994 Jan-Simon Pendry.
     39  * All rights reserved.
     40  *
     41  * This code is derived from software donated to Berkeley by
     42  * Jan-Simon Pendry.
     43  *
     44  * Redistribution and use in source and binary forms, with or without
     45  * modification, are permitted provided that the following conditions
     46  * are met:
     47  * 1. Redistributions of source code must retain the above copyright
     48  *    notice, this list of conditions and the following disclaimer.
     49  * 2. Redistributions in binary form must reproduce the above copyright
     50  *    notice, this list of conditions and the following disclaimer in the
     51  *    documentation and/or other materials provided with the distribution.
     52  * 3. All advertising materials mentioning features or use of this software
     53  *    must display the following acknowledgement:
     54  *	This product includes software developed by the University of
     55  *	California, Berkeley and its contributors.
     56  * 4. Neither the name of the University nor the names of its contributors
     57  *    may be used to endorse or promote products derived from this software
     58  *    without specific prior written permission.
     59  *
     60  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     61  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     62  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     63  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     64  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     65  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     66  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     67  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     68  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     69  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     70  * SUCH DAMAGE.
     71  *
     72  *	@(#)union.h	8.9 (Berkeley) 12/10/94
     73  */
     74 
     75 struct union_args {
     76 	char		*target;	/* Target of loopback  */
     77 	int		mntflags;	/* Options on the mount */
     78 };
     79 
     80 #define UNMNT_ABOVE	0x0001		/* Target appears below mount point */
     81 #define UNMNT_BELOW	0x0002		/* Target appears below mount point */
     82 #define UNMNT_REPLACE	0x0003		/* Target replaces mount point */
     83 #define UNMNT_OPMASK	0x0003
     84 
     85 #define UNMNT_BITS "\177\20" \
     86     "b\00above\0b\01below\0b\02replace\0"
     87 
     88 struct union_mount {
     89 	struct vnode	*um_uppervp;
     90 	struct vnode	*um_lowervp;
     91 	struct ucred	*um_cred;	/* Credentials of user calling mount */
     92 	int		um_cmode;	/* cmask from mount process */
     93 	int		um_op;		/* Operation mode */
     94 };
     95 
     96 #ifdef _KERNEL
     97 
     98 /*
     99  * DEFDIRMODE is the mode bits used to create a shadow directory.
    100  */
    101 #define	UN_DIRMODE	(S_IRWXU|S_IRWXG|S_IRWXO)
    102 #define	UN_FILEMODE	(S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH)
    103 
    104 /*
    105  * A cache of vnode references
    106  */
    107 struct union_node {
    108 	LIST_ENTRY(union_node)	un_cache;	/* Hash chain */
    109 	struct vnode		*un_vnode;	/* Back pointer */
    110 	struct vnode	        *un_uppervp;	/* overlaying object */
    111 	struct vnode	        *un_lowervp;	/* underlying object */
    112 	struct vnode		*un_dirvp;	/* Parent dir of uppervp */
    113 	struct vnode		*un_pvp;	/* Parent vnode */
    114 	char			*un_path;	/* saved component name */
    115 	int			un_hash;	/* saved un_path hash value */
    116 	int			un_openl;	/* # of opens on lowervp */
    117 	unsigned int		un_flags;
    118 	struct vnode		**un_dircache;	/* cached union stack */
    119 	off_t			un_uppersz;	/* size of upper object */
    120 	off_t			un_lowersz;	/* size of lower object */
    121 #ifdef DIAGNOSTIC
    122 	pid_t			un_pid;
    123 #endif
    124 };
    125 
    126 #define UN_WANTED	0x01
    127 #define UN_LOCKED	0x02
    128 #define UN_ULOCK	0x04		/* Upper node is locked */
    129 #define UN_KLOCK	0x08		/* Keep upper node locked on vput */
    130 #define UN_CACHED	0x10		/* In union cache */
    131 #define UN_DRAINING	0x20		/* upper node lock is draining */
    132 #define UN_DRAINED	0x40		/* upper node lock is drained */
    133 
    134 extern int union_allocvp __P((struct vnode **, struct mount *,
    135 				struct vnode *, struct vnode *,
    136 				struct componentname *, struct vnode *,
    137 				struct vnode *, int));
    138 extern int union_copyfile __P((struct vnode *, struct vnode *,
    139 					struct ucred *, struct proc *));
    140 extern int union_copyup __P((struct union_node *, int, struct ucred *,
    141 				struct proc *));
    142 extern void union_diruncache __P((struct union_node *));
    143 extern int union_dowhiteout __P((struct union_node *, struct ucred *,
    144 					struct proc *));
    145 extern int union_mkshadow __P((struct union_mount *, struct vnode *,
    146 				struct componentname *, struct vnode **));
    147 extern int union_mkwhiteout __P((struct union_mount *, struct vnode *,
    148 				struct componentname *, char *));
    149 extern int union_vn_create __P((struct vnode **, struct union_node *,
    150 				struct proc *));
    151 extern int union_cn_close __P((struct vnode *, int, struct ucred *,
    152 				struct proc *));
    153 extern void union_removed_upper __P((struct union_node *un));
    154 extern struct vnode *union_lowervp __P((struct vnode *));
    155 extern void union_newlower __P((struct union_node *, struct vnode *));
    156 extern void union_newupper __P((struct union_node *, struct vnode *));
    157 extern void union_newsize __P((struct vnode *, off_t, off_t));
    158 int union_readdirhook(struct vnode **, struct file *, struct proc *);
    159 
    160 #define	MOUNTTOUNIONMOUNT(mp) ((struct union_mount *)((mp)->mnt_data))
    161 #define	VTOUNION(vp) ((struct union_node *)(vp)->v_data)
    162 #define	UNIONTOV(un) ((un)->un_vnode)
    163 #define	LOWERVP(vp) (VTOUNION(vp)->un_lowervp)
    164 #define	UPPERVP(vp) (VTOUNION(vp)->un_uppervp)
    165 #define OTHERVP(vp) (UPPERVP(vp) ? UPPERVP(vp) : LOWERVP(vp))
    166 
    167 extern int (**union_vnodeop_p) __P((void *));
    168 
    169 void union_init __P((void));
    170 void union_done __P((void));
    171 int union_freevp __P((struct vnode *));
    172 
    173 #endif /* _KERNEL */
    174