xref: /openbmc/linux/fs/xfs/xfs_export.h (revision bbb774d9)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2005 Silicon Graphics, Inc.
4  * All Rights Reserved.
5  */
6 #ifndef __XFS_EXPORT_H__
7 #define __XFS_EXPORT_H__
8 
9 /*
10  * Common defines for code related to exporting XFS filesystems over NFS.
11  *
12  * The NFS fileid goes out on the wire as an array of
13  * 32bit unsigned ints in host order.  There are 5 possible
14  * formats.
15  *
16  * (1)	fileid_type=0x00
17  *	(no fileid data; handled by the generic code)
18  *
19  * (2)	fileid_type=0x01
20  *	inode-num
21  *	generation
22  *
23  * (3)	fileid_type=0x02
24  *	inode-num
25  *	generation
26  *	parent-inode-num
27  *	parent-generation
28  *
29  * (4)	fileid_type=0x81
30  *	inode-num-lo32
31  *	inode-num-hi32
32  *	generation
33  *
34  * (5)	fileid_type=0x82
35  *	inode-num-lo32
36  *	inode-num-hi32
37  *	generation
38  *	parent-inode-num-lo32
39  *	parent-inode-num-hi32
40  *	parent-generation
41  *
42  * Note, the NFS filehandle also includes an fsid portion which
43  * may have an inode number in it.  That number is hardcoded to
44  * 32bits and there is no way for XFS to intercept it.  In
45  * practice this means when exporting an XFS filesystem with 64bit
46  * inodes you should either export the mountpoint (rather than
47  * a subdirectory) or use the "fsid" export option.
48  */
49 
50 struct xfs_fid64 {
51 	u64 ino;
52 	u32 gen;
53 	u64 parent_ino;
54 	u32 parent_gen;
55 } __attribute__((packed));
56 
57 /* This flag goes on the wire.  Don't play with it. */
58 #define XFS_FILEID_TYPE_64FLAG	0x80	/* NFS fileid has 64bit inodes */
59 
60 #endif	/* __XFS_EXPORT_H__ */
61