]> git.proxmox.com Git - mirror_ubuntu-zesty-kernel.git/blame - include/linux/exportfs.h
mm: clean up mm_counter
[mirror_ubuntu-zesty-kernel.git] / include / linux / exportfs.h
CommitLineData
a5694255
CH
1#ifndef LINUX_EXPORTFS_H
2#define LINUX_EXPORTFS_H 1
3
4#include <linux/types.h>
5
6struct dentry;
2596110a 7struct inode;
a5694255 8struct super_block;
d37065cd 9struct vfsmount;
a5694255 10
6e91ea2b
CH
11/*
12 * The fileid_type identifies how the file within the filesystem is encoded.
13 * In theory this is freely set and parsed by the filesystem, but we try to
14 * stick to conventions so we can share some generic code and don't confuse
15 * sniffers like ethereal/wireshark.
16 *
17 * The filesystem must not use the value '0' or '0xff'.
18 */
19enum fid_type {
20 /*
21 * The root, or export point, of the filesystem.
22 * (Never actually passed down to the filesystem.
23 */
24 FILEID_ROOT = 0,
25
26 /*
27 * 32bit inode number, 32 bit generation number.
28 */
29 FILEID_INO32_GEN = 1,
30
31 /*
32 * 32bit inode number, 32 bit generation number,
33 * 32 bit parent directory inode number.
34 */
35 FILEID_INO32_GEN_PARENT = 2,
221e583a 36
e4464fac
DW
37 /*
38 * 64 bit object ID, 64 bit root object ID,
39 * 32 bit generation number.
40 */
41 FILEID_BTRFS_WITHOUT_PARENT = 0x4d,
42
43 /*
44 * 64 bit object ID, 64 bit root object ID,
45 * 32 bit generation number,
46 * 64 bit parent object ID, 32 bit parent generation.
47 */
48 FILEID_BTRFS_WITH_PARENT = 0x4e,
49
50 /*
51 * 64 bit object ID, 64 bit root object ID,
52 * 32 bit generation number,
53 * 64 bit parent object ID, 32 bit parent generation,
54 * 64 bit parent root object ID.
55 */
56 FILEID_BTRFS_WITH_PARENT_ROOT = 0x4f,
57
221e583a
RR
58 /*
59 * 32 bit block number, 16 bit partition reference,
60 * 16 bit unused, 32 bit generation number.
61 */
62 FILEID_UDF_WITHOUT_PARENT = 0x51,
63
64 /*
65 * 32 bit block number, 16 bit partition reference,
66 * 16 bit unused, 32 bit generation number,
67 * 32 bit parent block number, 32 bit parent generation number
68 */
69 FILEID_UDF_WITH_PARENT = 0x52,
6e91ea2b
CH
70};
71
72struct fid {
73 union {
74 struct {
75 u32 ino;
76 u32 gen;
77 u32 parent_ino;
78 u32 parent_gen;
79 } i32;
221e583a
RR
80 struct {
81 u32 block;
82 u16 partref;
83 u16 parent_partref;
84 u32 generation;
85 u32 parent_block;
86 u32 parent_generation;
87 } udf;
9078dc08 88 __u32 raw[0];
6e91ea2b
CH
89 };
90};
a5694255
CH
91
92/**
93 * struct export_operations - for nfsd to communicate with file systems
a5694255 94 * @encode_fh: encode a file handle fragment from a dentry
9b89ca7a
MD
95 * @fh_to_dentry: find the implied object and get a dentry for it
96 * @fh_to_parent: find the implied object's parent and get a dentry for it
a5694255
CH
97 * @get_name: find the name for a given inode in a given directory
98 * @get_parent: find the parent of a given directory
a5694255 99 *
dc7a0816 100 * See Documentation/filesystems/nfs/Exporting for details on how to use
e38f9817 101 * this interface correctly.
a5694255 102 *
a5694255
CH
103 * encode_fh:
104 * @encode_fh should store in the file handle fragment @fh (using at most
105 * @max_len bytes) information that can be used by @decode_fh to recover the
106 * file refered to by the &struct dentry @de. If the @connectable flag is
107 * set, the encode_fh() should store sufficient information so that a good
108 * attempt can be made to find not only the file but also it's place in the
109 * filesystem. This typically means storing a reference to de->d_parent in
110 * the filehandle fragment. encode_fh() should return the number of bytes
111 * stored or a negative error code such as %-ENOSPC
112 *
2596110a
CH
113 * fh_to_dentry:
114 * @fh_to_dentry is given a &struct super_block (@sb) and a file handle
115 * fragment (@fh, @fh_len). It should return a &struct dentry which refers
116 * to the same file that the file handle fragment refers to. If it cannot,
117 * it should return a %NULL pointer if the file was found but no acceptable
118 * &dentries were available, or an %ERR_PTR error code indicating why it
119 * couldn't be found (e.g. %ENOENT or %ENOMEM). Any suitable dentry can be
120 * returned including, if necessary, a new dentry created with d_alloc_root.
121 * The caller can then find any other extant dentries by following the
122 * d_alias links.
123 *
124 * fh_to_parent:
125 * Same as @fh_to_dentry, except that it returns a pointer to the parent
126 * dentry if it was encoded into the filehandle fragment by @encode_fh.
127 *
a5694255
CH
128 * get_name:
129 * @get_name should find a name for the given @child in the given @parent
130 * directory. The name should be stored in the @name (with the
131 * understanding that it is already pointing to a a %NAME_MAX+1 sized
132 * buffer. get_name() should return %0 on success, a negative error code
133 * or error. @get_name will be called without @parent->i_mutex held.
134 *
135 * get_parent:
136 * @get_parent should find the parent directory for the given @child which
137 * is also a directory. In the event that it cannot be found, or storage
138 * space cannot be allocated, a %ERR_PTR should be returned.
139 *
a5694255
CH
140 * Locking rules:
141 * get_parent is called with child->d_inode->i_mutex down
142 * get_name is not (which is possibly inconsistent)
143 */
144
145struct export_operations {
a5694255
CH
146 int (*encode_fh)(struct dentry *de, __u32 *fh, int *max_len,
147 int connectable);
2596110a
CH
148 struct dentry * (*fh_to_dentry)(struct super_block *sb, struct fid *fid,
149 int fh_len, int fh_type);
150 struct dentry * (*fh_to_parent)(struct super_block *sb, struct fid *fid,
151 int fh_len, int fh_type);
a5694255
CH
152 int (*get_name)(struct dentry *parent, char *name,
153 struct dentry *child);
154 struct dentry * (*get_parent)(struct dentry *child);
a5694255
CH
155};
156
6e91ea2b
CH
157extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid,
158 int *max_len, int connectable);
159extern struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid,
d37065cd
CH
160 int fh_len, int fileid_type, int (*acceptable)(void *, struct dentry *),
161 void *context);
162
2596110a
CH
163/*
164 * Generic helpers for filesystems.
165 */
166extern struct dentry *generic_fh_to_dentry(struct super_block *sb,
167 struct fid *fid, int fh_len, int fh_type,
168 struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen));
169extern struct dentry *generic_fh_to_parent(struct super_block *sb,
170 struct fid *fid, int fh_len, int fh_type,
171 struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen));
172
a5694255 173#endif /* LINUX_EXPORTFS_H */