xref: /linux/fs/xfs/xfs_export.h (revision 109d59b900e78834c66657dd4748fcedb9a1fe8d)
1 /*
2  * Copyright (c) 2005 Silicon Graphics, Inc.
3  * All Rights Reserved.
4  *
5  * This program is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU General Public License as
7  * published by the Free Software Foundation.
8  *
9  * This program is distributed in the hope that it would be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write the Free Software Foundation,
16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
17  */
18 #ifndef __XFS_EXPORT_H__
19 #define __XFS_EXPORT_H__
20 
21 /*
22  * Common defines for code related to exporting XFS filesystems over NFS.
23  *
24  * The NFS fileid goes out on the wire as an array of
25  * 32bit unsigned ints in host order.  There are 5 possible
26  * formats.
27  *
28  * (1)	fileid_type=0x00
29  *	(no fileid data; handled by the generic code)
30  *
31  * (2)	fileid_type=0x01
32  *	inode-num
33  *	generation
34  *
35  * (3)	fileid_type=0x02
36  *	inode-num
37  *	generation
38  *	parent-inode-num
39  *	parent-generation
40  *
41  * (4)	fileid_type=0x81
42  *	inode-num-lo32
43  *	inode-num-hi32
44  *	generation
45  *
46  * (5)	fileid_type=0x82
47  *	inode-num-lo32
48  *	inode-num-hi32
49  *	generation
50  *	parent-inode-num-lo32
51  *	parent-inode-num-hi32
52  *	parent-generation
53  *
54  * Note, the NFS filehandle also includes an fsid portion which
55  * may have an inode number in it.  That number is hardcoded to
56  * 32bits and there is no way for XFS to intercept it.  In
57  * practice this means when exporting an XFS filesystem with 64bit
58  * inodes you should either export the mountpoint (rather than
59  * a subdirectory) or use the "fsid" export option.
60  */
61 
62 struct xfs_fid64 {
63 	u64 ino;
64 	u32 gen;
65 	u64 parent_ino;
66 	u32 parent_gen;
67 } __attribute__((packed));
68 
69 /* This flag goes on the wire.  Don't play with it. */
70 #define XFS_FILEID_TYPE_64FLAG	0x80	/* NFS fileid has 64bit inodes */
71 
72 #endif	/* __XFS_EXPORT_H__ */
73