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a5694255 CH |
1 | #ifndef LINUX_EXPORTFS_H |
2 | #define LINUX_EXPORTFS_H 1 | |
3 | ||
4 | #include <linux/types.h> | |
5 | ||
6 | struct dentry; | |
2596110a | 7 | struct inode; |
a5694255 | 8 | struct super_block; |
d37065cd | 9 | struct vfsmount; |
a5694255 | 10 | |
990d6c2d AK |
11 | /* limit the handle size to NFSv4 handle size now */ |
12 | #define MAX_HANDLE_SZ 128 | |
13 | ||
6e91ea2b CH |
14 | /* |
15 | * The fileid_type identifies how the file within the filesystem is encoded. | |
16 | * In theory this is freely set and parsed by the filesystem, but we try to | |
17 | * stick to conventions so we can share some generic code and don't confuse | |
18 | * sniffers like ethereal/wireshark. | |
19 | * | |
20 | * The filesystem must not use the value '0' or '0xff'. | |
21 | */ | |
22 | enum fid_type { | |
23 | /* | |
24 | * The root, or export point, of the filesystem. | |
25 | * (Never actually passed down to the filesystem. | |
26 | */ | |
27 | FILEID_ROOT = 0, | |
28 | ||
29 | /* | |
30 | * 32bit inode number, 32 bit generation number. | |
31 | */ | |
32 | FILEID_INO32_GEN = 1, | |
33 | ||
34 | /* | |
35 | * 32bit inode number, 32 bit generation number, | |
36 | * 32 bit parent directory inode number. | |
37 | */ | |
38 | FILEID_INO32_GEN_PARENT = 2, | |
221e583a | 39 | |
e4464fac DW |
40 | /* |
41 | * 64 bit object ID, 64 bit root object ID, | |
42 | * 32 bit generation number. | |
43 | */ | |
44 | FILEID_BTRFS_WITHOUT_PARENT = 0x4d, | |
45 | ||
46 | /* | |
47 | * 64 bit object ID, 64 bit root object ID, | |
48 | * 32 bit generation number, | |
49 | * 64 bit parent object ID, 32 bit parent generation. | |
50 | */ | |
51 | FILEID_BTRFS_WITH_PARENT = 0x4e, | |
52 | ||
53 | /* | |
54 | * 64 bit object ID, 64 bit root object ID, | |
55 | * 32 bit generation number, | |
56 | * 64 bit parent object ID, 32 bit parent generation, | |
57 | * 64 bit parent root object ID. | |
58 | */ | |
59 | FILEID_BTRFS_WITH_PARENT_ROOT = 0x4f, | |
60 | ||
221e583a RR |
61 | /* |
62 | * 32 bit block number, 16 bit partition reference, | |
63 | * 16 bit unused, 32 bit generation number. | |
64 | */ | |
65 | FILEID_UDF_WITHOUT_PARENT = 0x51, | |
66 | ||
67 | /* | |
68 | * 32 bit block number, 16 bit partition reference, | |
69 | * 16 bit unused, 32 bit generation number, | |
70 | * 32 bit parent block number, 32 bit parent generation number | |
71 | */ | |
72 | FILEID_UDF_WITH_PARENT = 0x52, | |
8e656fd5 RK |
73 | |
74 | /* | |
75 | * 64 bit checkpoint number, 64 bit inode number, | |
76 | * 32 bit generation number. | |
77 | */ | |
78 | FILEID_NILFS_WITHOUT_PARENT = 0x61, | |
79 | ||
80 | /* | |
81 | * 64 bit checkpoint number, 64 bit inode number, | |
82 | * 32 bit generation number, 32 bit parent generation. | |
83 | * 64 bit parent inode number. | |
84 | */ | |
85 | FILEID_NILFS_WITH_PARENT = 0x62, | |
6e91ea2b CH |
86 | }; |
87 | ||
88 | struct fid { | |
89 | union { | |
90 | struct { | |
91 | u32 ino; | |
92 | u32 gen; | |
93 | u32 parent_ino; | |
94 | u32 parent_gen; | |
95 | } i32; | |
221e583a RR |
96 | struct { |
97 | u32 block; | |
98 | u16 partref; | |
99 | u16 parent_partref; | |
100 | u32 generation; | |
101 | u32 parent_block; | |
102 | u32 parent_generation; | |
103 | } udf; | |
9078dc08 | 104 | __u32 raw[0]; |
6e91ea2b CH |
105 | }; |
106 | }; | |
a5694255 CH |
107 | |
108 | /** | |
109 | * struct export_operations - for nfsd to communicate with file systems | |
a5694255 | 110 | * @encode_fh: encode a file handle fragment from a dentry |
9b89ca7a MD |
111 | * @fh_to_dentry: find the implied object and get a dentry for it |
112 | * @fh_to_parent: find the implied object's parent and get a dentry for it | |
a5694255 CH |
113 | * @get_name: find the name for a given inode in a given directory |
114 | * @get_parent: find the parent of a given directory | |
f501912a | 115 | * @commit_metadata: commit metadata changes to stable storage |
a5694255 | 116 | * |
dc7a0816 | 117 | * See Documentation/filesystems/nfs/Exporting for details on how to use |
e38f9817 | 118 | * this interface correctly. |
a5694255 | 119 | * |
a5694255 CH |
120 | * encode_fh: |
121 | * @encode_fh should store in the file handle fragment @fh (using at most | |
122 | * @max_len bytes) information that can be used by @decode_fh to recover the | |
25985edc | 123 | * file referred to by the &struct dentry @de. If the @connectable flag is |
a5694255 CH |
124 | * set, the encode_fh() should store sufficient information so that a good |
125 | * attempt can be made to find not only the file but also it's place in the | |
126 | * filesystem. This typically means storing a reference to de->d_parent in | |
5fe0c237 AK |
127 | * the filehandle fragment. encode_fh() should return the fileid_type on |
128 | * success and on error returns 255 (if the space needed to encode fh is | |
129 | * greater than @max_len*4 bytes). On error @max_len contains the minimum | |
130 | * size(in 4 byte unit) needed to encode the file handle. | |
a5694255 | 131 | * |
2596110a CH |
132 | * fh_to_dentry: |
133 | * @fh_to_dentry is given a &struct super_block (@sb) and a file handle | |
134 | * fragment (@fh, @fh_len). It should return a &struct dentry which refers | |
135 | * to the same file that the file handle fragment refers to. If it cannot, | |
136 | * it should return a %NULL pointer if the file was found but no acceptable | |
137 | * &dentries were available, or an %ERR_PTR error code indicating why it | |
138 | * couldn't be found (e.g. %ENOENT or %ENOMEM). Any suitable dentry can be | |
139 | * returned including, if necessary, a new dentry created with d_alloc_root. | |
140 | * The caller can then find any other extant dentries by following the | |
141 | * d_alias links. | |
142 | * | |
143 | * fh_to_parent: | |
144 | * Same as @fh_to_dentry, except that it returns a pointer to the parent | |
145 | * dentry if it was encoded into the filehandle fragment by @encode_fh. | |
146 | * | |
a5694255 CH |
147 | * get_name: |
148 | * @get_name should find a name for the given @child in the given @parent | |
149 | * directory. The name should be stored in the @name (with the | |
150 | * understanding that it is already pointing to a a %NAME_MAX+1 sized | |
151 | * buffer. get_name() should return %0 on success, a negative error code | |
152 | * or error. @get_name will be called without @parent->i_mutex held. | |
153 | * | |
154 | * get_parent: | |
155 | * @get_parent should find the parent directory for the given @child which | |
156 | * is also a directory. In the event that it cannot be found, or storage | |
157 | * space cannot be allocated, a %ERR_PTR should be returned. | |
158 | * | |
f501912a BM |
159 | * commit_metadata: |
160 | * @commit_metadata should commit metadata changes to stable storage. | |
161 | * | |
a5694255 CH |
162 | * Locking rules: |
163 | * get_parent is called with child->d_inode->i_mutex down | |
164 | * get_name is not (which is possibly inconsistent) | |
165 | */ | |
166 | ||
167 | struct export_operations { | |
a5694255 CH |
168 | int (*encode_fh)(struct dentry *de, __u32 *fh, int *max_len, |
169 | int connectable); | |
2596110a CH |
170 | struct dentry * (*fh_to_dentry)(struct super_block *sb, struct fid *fid, |
171 | int fh_len, int fh_type); | |
172 | struct dentry * (*fh_to_parent)(struct super_block *sb, struct fid *fid, | |
173 | int fh_len, int fh_type); | |
a5694255 CH |
174 | int (*get_name)(struct dentry *parent, char *name, |
175 | struct dentry *child); | |
176 | struct dentry * (*get_parent)(struct dentry *child); | |
f501912a | 177 | int (*commit_metadata)(struct inode *inode); |
a5694255 CH |
178 | }; |
179 | ||
6e91ea2b CH |
180 | extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid, |
181 | int *max_len, int connectable); | |
182 | extern struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid, | |
d37065cd CH |
183 | int fh_len, int fileid_type, int (*acceptable)(void *, struct dentry *), |
184 | void *context); | |
185 | ||
2596110a CH |
186 | /* |
187 | * Generic helpers for filesystems. | |
188 | */ | |
189 | extern struct dentry *generic_fh_to_dentry(struct super_block *sb, | |
190 | struct fid *fid, int fh_len, int fh_type, | |
191 | struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen)); | |
192 | extern struct dentry *generic_fh_to_parent(struct super_block *sb, | |
193 | struct fid *fid, int fh_len, int fh_type, | |
194 | struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen)); | |
195 | ||
a5694255 | 196 | #endif /* LINUX_EXPORTFS_H */ |