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1 | #ifndef LINUX_EXPORTFS_H | |
2 | #define LINUX_EXPORTFS_H 1 | |
3 | ||
4 | #include <linux/types.h> | |
5 | ||
6 | struct dentry; | |
7 | struct iattr; | |
8 | struct inode; | |
9 | struct iomap; | |
10 | struct super_block; | |
11 | struct vfsmount; | |
12 | ||
13 | /* limit the handle size to NFSv4 handle size now */ | |
14 | #define MAX_HANDLE_SZ 128 | |
15 | ||
16 | /* | |
17 | * The fileid_type identifies how the file within the filesystem is encoded. | |
18 | * In theory this is freely set and parsed by the filesystem, but we try to | |
19 | * stick to conventions so we can share some generic code and don't confuse | |
20 | * sniffers like ethereal/wireshark. | |
21 | * | |
22 | * The filesystem must not use the value '0' or '0xff'. | |
23 | */ | |
24 | enum fid_type { | |
25 | /* | |
26 | * The root, or export point, of the filesystem. | |
27 | * (Never actually passed down to the filesystem. | |
28 | */ | |
29 | FILEID_ROOT = 0, | |
30 | ||
31 | /* | |
32 | * 32bit inode number, 32 bit generation number. | |
33 | */ | |
34 | FILEID_INO32_GEN = 1, | |
35 | ||
36 | /* | |
37 | * 32bit inode number, 32 bit generation number, | |
38 | * 32 bit parent directory inode number. | |
39 | */ | |
40 | FILEID_INO32_GEN_PARENT = 2, | |
41 | ||
42 | /* | |
43 | * 64 bit object ID, 64 bit root object ID, | |
44 | * 32 bit generation number. | |
45 | */ | |
46 | FILEID_BTRFS_WITHOUT_PARENT = 0x4d, | |
47 | ||
48 | /* | |
49 | * 64 bit object ID, 64 bit root object ID, | |
50 | * 32 bit generation number, | |
51 | * 64 bit parent object ID, 32 bit parent generation. | |
52 | */ | |
53 | FILEID_BTRFS_WITH_PARENT = 0x4e, | |
54 | ||
55 | /* | |
56 | * 64 bit object ID, 64 bit root object ID, | |
57 | * 32 bit generation number, | |
58 | * 64 bit parent object ID, 32 bit parent generation, | |
59 | * 64 bit parent root object ID. | |
60 | */ | |
61 | FILEID_BTRFS_WITH_PARENT_ROOT = 0x4f, | |
62 | ||
63 | /* | |
64 | * 32 bit block number, 16 bit partition reference, | |
65 | * 16 bit unused, 32 bit generation number. | |
66 | */ | |
67 | FILEID_UDF_WITHOUT_PARENT = 0x51, | |
68 | ||
69 | /* | |
70 | * 32 bit block number, 16 bit partition reference, | |
71 | * 16 bit unused, 32 bit generation number, | |
72 | * 32 bit parent block number, 32 bit parent generation number | |
73 | */ | |
74 | FILEID_UDF_WITH_PARENT = 0x52, | |
75 | ||
76 | /* | |
77 | * 64 bit checkpoint number, 64 bit inode number, | |
78 | * 32 bit generation number. | |
79 | */ | |
80 | FILEID_NILFS_WITHOUT_PARENT = 0x61, | |
81 | ||
82 | /* | |
83 | * 64 bit checkpoint number, 64 bit inode number, | |
84 | * 32 bit generation number, 32 bit parent generation. | |
85 | * 64 bit parent inode number. | |
86 | */ | |
87 | FILEID_NILFS_WITH_PARENT = 0x62, | |
88 | ||
89 | /* | |
90 | * 32 bit generation number, 40 bit i_pos. | |
91 | */ | |
92 | FILEID_FAT_WITHOUT_PARENT = 0x71, | |
93 | ||
94 | /* | |
95 | * 32 bit generation number, 40 bit i_pos, | |
96 | * 32 bit parent generation number, 40 bit parent i_pos | |
97 | */ | |
98 | FILEID_FAT_WITH_PARENT = 0x72, | |
99 | ||
100 | /* | |
101 | * 128 bit child FID (struct lu_fid) | |
102 | * 128 bit parent FID (struct lu_fid) | |
103 | */ | |
104 | FILEID_LUSTRE = 0x97, | |
105 | ||
106 | /* | |
107 | * Filesystems must not use 0xff file ID. | |
108 | */ | |
109 | FILEID_INVALID = 0xff, | |
110 | }; | |
111 | ||
112 | struct fid { | |
113 | union { | |
114 | struct { | |
115 | u32 ino; | |
116 | u32 gen; | |
117 | u32 parent_ino; | |
118 | u32 parent_gen; | |
119 | } i32; | |
120 | struct { | |
121 | u32 block; | |
122 | u16 partref; | |
123 | u16 parent_partref; | |
124 | u32 generation; | |
125 | u32 parent_block; | |
126 | u32 parent_generation; | |
127 | } udf; | |
128 | __u32 raw[0]; | |
129 | }; | |
130 | }; | |
131 | ||
132 | /** | |
133 | * struct export_operations - for nfsd to communicate with file systems | |
134 | * @encode_fh: encode a file handle fragment from a dentry | |
135 | * @fh_to_dentry: find the implied object and get a dentry for it | |
136 | * @fh_to_parent: find the implied object's parent and get a dentry for it | |
137 | * @get_name: find the name for a given inode in a given directory | |
138 | * @get_parent: find the parent of a given directory | |
139 | * @commit_metadata: commit metadata changes to stable storage | |
140 | * | |
141 | * See Documentation/filesystems/nfs/Exporting for details on how to use | |
142 | * this interface correctly. | |
143 | * | |
144 | * encode_fh: | |
145 | * @encode_fh should store in the file handle fragment @fh (using at most | |
146 | * @max_len bytes) information that can be used by @decode_fh to recover the | |
147 | * file referred to by the &struct dentry @de. If the @connectable flag is | |
148 | * set, the encode_fh() should store sufficient information so that a good | |
149 | * attempt can be made to find not only the file but also it's place in the | |
150 | * filesystem. This typically means storing a reference to de->d_parent in | |
151 | * the filehandle fragment. encode_fh() should return the fileid_type on | |
152 | * success and on error returns 255 (if the space needed to encode fh is | |
153 | * greater than @max_len*4 bytes). On error @max_len contains the minimum | |
154 | * size(in 4 byte unit) needed to encode the file handle. | |
155 | * | |
156 | * fh_to_dentry: | |
157 | * @fh_to_dentry is given a &struct super_block (@sb) and a file handle | |
158 | * fragment (@fh, @fh_len). It should return a &struct dentry which refers | |
159 | * to the same file that the file handle fragment refers to. If it cannot, | |
160 | * it should return a %NULL pointer if the file cannot be found, or an | |
161 | * %ERR_PTR error code of %ENOMEM if a memory allocation failure occurred. | |
162 | * Any other error code is treated like %NULL, and will cause an %ESTALE error | |
163 | * for callers of exportfs_decode_fh(). | |
164 | * Any suitable dentry can be returned including, if necessary, a new dentry | |
165 | * created with d_alloc_root. The caller can then find any other extant | |
166 | * dentries by following the d_alias links. | |
167 | * | |
168 | * fh_to_parent: | |
169 | * Same as @fh_to_dentry, except that it returns a pointer to the parent | |
170 | * dentry if it was encoded into the filehandle fragment by @encode_fh. | |
171 | * | |
172 | * get_name: | |
173 | * @get_name should find a name for the given @child in the given @parent | |
174 | * directory. The name should be stored in the @name (with the | |
175 | * understanding that it is already pointing to a a %NAME_MAX+1 sized | |
176 | * buffer. get_name() should return %0 on success, a negative error code | |
177 | * or error. @get_name will be called without @parent->i_mutex held. | |
178 | * | |
179 | * get_parent: | |
180 | * @get_parent should find the parent directory for the given @child which | |
181 | * is also a directory. In the event that it cannot be found, or storage | |
182 | * space cannot be allocated, a %ERR_PTR should be returned. | |
183 | * | |
184 | * commit_metadata: | |
185 | * @commit_metadata should commit metadata changes to stable storage. | |
186 | * | |
187 | * Locking rules: | |
188 | * get_parent is called with child->d_inode->i_mutex down | |
189 | * get_name is not (which is possibly inconsistent) | |
190 | */ | |
191 | ||
192 | struct export_operations { | |
193 | int (*encode_fh)(struct inode *inode, __u32 *fh, int *max_len, | |
194 | struct inode *parent); | |
195 | struct dentry * (*fh_to_dentry)(struct super_block *sb, struct fid *fid, | |
196 | int fh_len, int fh_type); | |
197 | struct dentry * (*fh_to_parent)(struct super_block *sb, struct fid *fid, | |
198 | int fh_len, int fh_type); | |
199 | int (*get_name)(struct dentry *parent, char *name, | |
200 | struct dentry *child); | |
201 | struct dentry * (*get_parent)(struct dentry *child); | |
202 | int (*commit_metadata)(struct inode *inode); | |
203 | ||
204 | int (*get_uuid)(struct super_block *sb, u8 *buf, u32 *len, u64 *offset); | |
205 | int (*map_blocks)(struct inode *inode, loff_t offset, | |
206 | u64 len, struct iomap *iomap, | |
207 | bool write, u32 *device_generation); | |
208 | int (*commit_blocks)(struct inode *inode, struct iomap *iomaps, | |
209 | int nr_iomaps, struct iattr *iattr); | |
210 | }; | |
211 | ||
212 | extern int exportfs_encode_inode_fh(struct inode *inode, struct fid *fid, | |
213 | int *max_len, struct inode *parent); | |
214 | extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid, | |
215 | int *max_len, int connectable); | |
216 | extern struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid, | |
217 | int fh_len, int fileid_type, int (*acceptable)(void *, struct dentry *), | |
218 | void *context); | |
219 | ||
220 | /* | |
221 | * Generic helpers for filesystems. | |
222 | */ | |
223 | extern struct dentry *generic_fh_to_dentry(struct super_block *sb, | |
224 | struct fid *fid, int fh_len, int fh_type, | |
225 | struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen)); | |
226 | extern struct dentry *generic_fh_to_parent(struct super_block *sb, | |
227 | struct fid *fid, int fh_len, int fh_type, | |
228 | struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen)); | |
229 | ||
230 | #endif /* LINUX_EXPORTFS_H */ |