1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
|
#ifndef LINUX_EXPORTFS_H
#define LINUX_EXPORTFS_H 1
#include <linux/types.h>
struct dentry;
struct inode;
struct super_block;
struct vfsmount;
/*
* The fileid_type identifies how the file within the filesystem is encoded.
* In theory this is freely set and parsed by the filesystem, but we try to
* stick to conventions so we can share some generic code and don't confuse
* sniffers like ethereal/wireshark.
*
* The filesystem must not use the value '0' or '0xff'.
*/
enum fid_type {
/*
* The root, or export point, of the filesystem.
* (Never actually passed down to the filesystem.
*/
FILEID_ROOT = 0,
/*
* 32bit inode number, 32 bit generation number.
*/
FILEID_INO32_GEN = 1,
/*
* 32bit inode number, 32 bit generation number,
* 32 bit parent directory inode number.
*/
FILEID_INO32_GEN_PARENT = 2,
/*
* 64 bit object ID, 64 bit root object ID,
* 32 bit generation number.
*/
FILEID_BTRFS_WITHOUT_PARENT = 0x4d,
/*
* 64 bit object ID, 64 bit root object ID,
* 32 bit generation number,
* 64 bit parent object ID, 32 bit parent generation.
*/
FILEID_BTRFS_WITH_PARENT = 0x4e,
/*
* 64 bit object ID, 64 bit root object ID,
* 32 bit generation number,
* 64 bit parent object ID, 32 bit parent generation,
* 64 bit parent root object ID.
*/
FILEID_BTRFS_WITH_PARENT_ROOT = 0x4f,
/*
* 32 bit block number, 16 bit partition reference,
* 16 bit unused, 32 bit generation number.
*/
FILEID_UDF_WITHOUT_PARENT = 0x51,
/*
* 32 bit block number, 16 bit partition reference,
* 16 bit unused, 32 bit generation number,
* 32 bit parent block number, 32 bit parent generation number
*/
FILEID_UDF_WITH_PARENT = 0x52,
};
struct fid {
union {
struct {
u32 ino;
u32 gen;
u32 parent_ino;
u32 parent_gen;
} i32;
struct {
u32 block;
u16 partref;
u16 parent_partref;
u32 generation;
u32 parent_block;
u32 parent_generation;
} udf;
__u32 raw[0];
};
};
/**
* struct export_operations - for nfsd to communicate with file systems
* @encode_fh: encode a file handle fragment from a dentry
* @fh_to_dentry: find the implied object and get a dentry for it
* @fh_to_parent: find the implied object's parent and get a dentry for it
* @get_name: find the name for a given inode in a given directory
* @get_parent: find the parent of a given directory
*
* See Documentation/filesystems/Exporting for details on how to use
* this interface correctly.
*
* encode_fh:
* @encode_fh should store in the file handle fragment @fh (using at most
* @max_len bytes) information that can be used by @decode_fh to recover the
* file refered to by the &struct dentry @de. If the @connectable flag is
* set, the encode_fh() should store sufficient information so that a good
* attempt can be made to find not only the file but also it's place in the
* filesystem. This typically means storing a reference to de->d_parent in
* the filehandle fragment. encode_fh() should return the number of bytes
* stored or a negative error code such as %-ENOSPC
*
* fh_to_dentry:
* @fh_to_dentry is given a &struct super_block (@sb) and a file handle
* fragment (@fh, @fh_len). It should return a &struct dentry which refers
* to the same file that the file handle fragment refers to. If it cannot,
* it should return a %NULL pointer if the file was found but no acceptable
* &dentries were available, or an %ERR_PTR error code indicating why it
* couldn't be found (e.g. %ENOENT or %ENOMEM). Any suitable dentry can be
* returned including, if necessary, a new dentry created with d_alloc_root.
* The caller can then find any other extant dentries by following the
* d_alias links.
*
* fh_to_parent:
* Same as @fh_to_dentry, except that it returns a pointer to the parent
* dentry if it was encoded into the filehandle fragment by @encode_fh.
*
* get_name:
* @get_name should find a name for the given @child in the given @parent
* directory. The name should be stored in the @name (with the
* understanding that it is already pointing to a a %NAME_MAX+1 sized
* buffer. get_name() should return %0 on success, a negative error code
* or error. @get_name will be called without @parent->i_mutex held.
*
* get_parent:
* @get_parent should find the parent directory for the given @child which
* is also a directory. In the event that it cannot be found, or storage
* space cannot be allocated, a %ERR_PTR should be returned.
*
* Locking rules:
* get_parent is called with child->d_inode->i_mutex down
* get_name is not (which is possibly inconsistent)
*/
struct export_operations {
int (*encode_fh)(struct dentry *de, __u32 *fh, int *max_len,
int connectable);
struct dentry * (*fh_to_dentry)(struct super_block *sb, struct fid *fid,
int fh_len, int fh_type);
struct dentry * (*fh_to_parent)(struct super_block *sb, struct fid *fid,
int fh_len, int fh_type);
int (*get_name)(struct dentry *parent, char *name,
struct dentry *child);
struct dentry * (*get_parent)(struct dentry *child);
};
extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid,
int *max_len, int connectable);
extern struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid,
int fh_len, int fileid_type, int (*acceptable)(void *, struct dentry *),
void *context);
/*
* Generic helpers for filesystems.
*/
extern struct dentry *generic_fh_to_dentry(struct super_block *sb,
struct fid *fid, int fh_len, int fh_type,
struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen));
extern struct dentry *generic_fh_to_parent(struct super_block *sb,
struct fid *fid, int fh_len, int fh_type,
struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen));
#endif /* LINUX_EXPORTFS_H */
|
