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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
a5694255 CH |
2 | #ifndef LINUX_EXPORTFS_H |
3 | #define LINUX_EXPORTFS_H 1 | |
4 | ||
5 | #include <linux/types.h> | |
6 | ||
7 | struct dentry; | |
7fbc1067 | 8 | struct iattr; |
2596110a | 9 | struct inode; |
199a31c6 | 10 | struct iomap; |
a5694255 | 11 | struct super_block; |
d37065cd | 12 | struct vfsmount; |
a5694255 | 13 | |
990d6c2d AK |
14 | /* limit the handle size to NFSv4 handle size now */ |
15 | #define MAX_HANDLE_SZ 128 | |
16 | ||
6e91ea2b CH |
17 | /* |
18 | * The fileid_type identifies how the file within the filesystem is encoded. | |
19 | * In theory this is freely set and parsed by the filesystem, but we try to | |
20 | * stick to conventions so we can share some generic code and don't confuse | |
21 | * sniffers like ethereal/wireshark. | |
22 | * | |
23 | * The filesystem must not use the value '0' or '0xff'. | |
24 | */ | |
25 | enum fid_type { | |
26 | /* | |
27 | * The root, or export point, of the filesystem. | |
28 | * (Never actually passed down to the filesystem. | |
29 | */ | |
30 | FILEID_ROOT = 0, | |
31 | ||
32 | /* | |
33 | * 32bit inode number, 32 bit generation number. | |
34 | */ | |
35 | FILEID_INO32_GEN = 1, | |
36 | ||
37 | /* | |
38 | * 32bit inode number, 32 bit generation number, | |
39 | * 32 bit parent directory inode number. | |
40 | */ | |
41 | FILEID_INO32_GEN_PARENT = 2, | |
221e583a | 42 | |
e4464fac DW |
43 | /* |
44 | * 64 bit object ID, 64 bit root object ID, | |
45 | * 32 bit generation number. | |
46 | */ | |
47 | FILEID_BTRFS_WITHOUT_PARENT = 0x4d, | |
48 | ||
49 | /* | |
50 | * 64 bit object ID, 64 bit root object ID, | |
51 | * 32 bit generation number, | |
52 | * 64 bit parent object ID, 32 bit parent generation. | |
53 | */ | |
54 | FILEID_BTRFS_WITH_PARENT = 0x4e, | |
55 | ||
56 | /* | |
57 | * 64 bit object ID, 64 bit root object ID, | |
58 | * 32 bit generation number, | |
59 | * 64 bit parent object ID, 32 bit parent generation, | |
60 | * 64 bit parent root object ID. | |
61 | */ | |
62 | FILEID_BTRFS_WITH_PARENT_ROOT = 0x4f, | |
63 | ||
221e583a RR |
64 | /* |
65 | * 32 bit block number, 16 bit partition reference, | |
66 | * 16 bit unused, 32 bit generation number. | |
67 | */ | |
68 | FILEID_UDF_WITHOUT_PARENT = 0x51, | |
69 | ||
70 | /* | |
71 | * 32 bit block number, 16 bit partition reference, | |
72 | * 16 bit unused, 32 bit generation number, | |
73 | * 32 bit parent block number, 32 bit parent generation number | |
74 | */ | |
75 | FILEID_UDF_WITH_PARENT = 0x52, | |
8e656fd5 RK |
76 | |
77 | /* | |
78 | * 64 bit checkpoint number, 64 bit inode number, | |
79 | * 32 bit generation number. | |
80 | */ | |
81 | FILEID_NILFS_WITHOUT_PARENT = 0x61, | |
82 | ||
83 | /* | |
84 | * 64 bit checkpoint number, 64 bit inode number, | |
85 | * 32 bit generation number, 32 bit parent generation. | |
86 | * 64 bit parent inode number. | |
87 | */ | |
88 | FILEID_NILFS_WITH_PARENT = 0x62, | |
216b6cbd | 89 | |
ea3983ac NJ |
90 | /* |
91 | * 32 bit generation number, 40 bit i_pos. | |
92 | */ | |
93 | FILEID_FAT_WITHOUT_PARENT = 0x71, | |
94 | ||
95 | /* | |
96 | * 32 bit generation number, 40 bit i_pos, | |
97 | * 32 bit parent generation number, 40 bit parent i_pos | |
98 | */ | |
99 | FILEID_FAT_WITH_PARENT = 0x72, | |
100 | ||
cb776592 DE |
101 | /* |
102 | * 128 bit child FID (struct lu_fid) | |
103 | * 128 bit parent FID (struct lu_fid) | |
104 | */ | |
105 | FILEID_LUSTRE = 0x97, | |
106 | ||
33c5ac91 TH |
107 | /* |
108 | * 64 bit unique kernfs id | |
109 | */ | |
110 | FILEID_KERNFS = 0xfe, | |
111 | ||
216b6cbd NJ |
112 | /* |
113 | * Filesystems must not use 0xff file ID. | |
114 | */ | |
115 | FILEID_INVALID = 0xff, | |
6e91ea2b CH |
116 | }; |
117 | ||
118 | struct fid { | |
119 | union { | |
120 | struct { | |
121 | u32 ino; | |
122 | u32 gen; | |
123 | u32 parent_ino; | |
124 | u32 parent_gen; | |
125 | } i32; | |
221e583a RR |
126 | struct { |
127 | u32 block; | |
128 | u16 partref; | |
129 | u16 parent_partref; | |
130 | u32 generation; | |
131 | u32 parent_block; | |
132 | u32 parent_generation; | |
133 | } udf; | |
9078dc08 | 134 | __u32 raw[0]; |
6e91ea2b CH |
135 | }; |
136 | }; | |
a5694255 CH |
137 | |
138 | /** | |
139 | * struct export_operations - for nfsd to communicate with file systems | |
a5694255 | 140 | * @encode_fh: encode a file handle fragment from a dentry |
9b89ca7a MD |
141 | * @fh_to_dentry: find the implied object and get a dentry for it |
142 | * @fh_to_parent: find the implied object's parent and get a dentry for it | |
a5694255 CH |
143 | * @get_name: find the name for a given inode in a given directory |
144 | * @get_parent: find the parent of a given directory | |
f501912a | 145 | * @commit_metadata: commit metadata changes to stable storage |
a5694255 | 146 | * |
ec23eb54 | 147 | * See Documentation/filesystems/nfs/exporting.rst for details on how to use |
e38f9817 | 148 | * this interface correctly. |
a5694255 | 149 | * |
a5694255 CH |
150 | * encode_fh: |
151 | * @encode_fh should store in the file handle fragment @fh (using at most | |
152 | * @max_len bytes) information that can be used by @decode_fh to recover the | |
25985edc | 153 | * file referred to by the &struct dentry @de. If the @connectable flag is |
a5694255 CH |
154 | * set, the encode_fh() should store sufficient information so that a good |
155 | * attempt can be made to find not only the file but also it's place in the | |
156 | * filesystem. This typically means storing a reference to de->d_parent in | |
5fe0c237 AK |
157 | * the filehandle fragment. encode_fh() should return the fileid_type on |
158 | * success and on error returns 255 (if the space needed to encode fh is | |
159 | * greater than @max_len*4 bytes). On error @max_len contains the minimum | |
160 | * size(in 4 byte unit) needed to encode the file handle. | |
a5694255 | 161 | * |
2596110a CH |
162 | * fh_to_dentry: |
163 | * @fh_to_dentry is given a &struct super_block (@sb) and a file handle | |
164 | * fragment (@fh, @fh_len). It should return a &struct dentry which refers | |
165 | * to the same file that the file handle fragment refers to. If it cannot, | |
09bb8bff N |
166 | * it should return a %NULL pointer if the file cannot be found, or an |
167 | * %ERR_PTR error code of %ENOMEM if a memory allocation failure occurred. | |
168 | * Any other error code is treated like %NULL, and will cause an %ESTALE error | |
169 | * for callers of exportfs_decode_fh(). | |
170 | * Any suitable dentry can be returned including, if necessary, a new dentry | |
171 | * created with d_alloc_root. The caller can then find any other extant | |
172 | * dentries by following the d_alias links. | |
2596110a CH |
173 | * |
174 | * fh_to_parent: | |
175 | * Same as @fh_to_dentry, except that it returns a pointer to the parent | |
176 | * dentry if it was encoded into the filehandle fragment by @encode_fh. | |
177 | * | |
a5694255 CH |
178 | * get_name: |
179 | * @get_name should find a name for the given @child in the given @parent | |
180 | * directory. The name should be stored in the @name (with the | |
181 | * understanding that it is already pointing to a a %NAME_MAX+1 sized | |
182 | * buffer. get_name() should return %0 on success, a negative error code | |
183 | * or error. @get_name will be called without @parent->i_mutex held. | |
184 | * | |
185 | * get_parent: | |
186 | * @get_parent should find the parent directory for the given @child which | |
187 | * is also a directory. In the event that it cannot be found, or storage | |
188 | * space cannot be allocated, a %ERR_PTR should be returned. | |
189 | * | |
f501912a BM |
190 | * commit_metadata: |
191 | * @commit_metadata should commit metadata changes to stable storage. | |
192 | * | |
a5694255 CH |
193 | * Locking rules: |
194 | * get_parent is called with child->d_inode->i_mutex down | |
195 | * get_name is not (which is possibly inconsistent) | |
196 | */ | |
197 | ||
198 | struct export_operations { | |
b0b0382b AV |
199 | int (*encode_fh)(struct inode *inode, __u32 *fh, int *max_len, |
200 | struct inode *parent); | |
2596110a CH |
201 | struct dentry * (*fh_to_dentry)(struct super_block *sb, struct fid *fid, |
202 | int fh_len, int fh_type); | |
203 | struct dentry * (*fh_to_parent)(struct super_block *sb, struct fid *fid, | |
204 | int fh_len, int fh_type); | |
a5694255 CH |
205 | int (*get_name)(struct dentry *parent, char *name, |
206 | struct dentry *child); | |
207 | struct dentry * (*get_parent)(struct dentry *child); | |
f501912a | 208 | int (*commit_metadata)(struct inode *inode); |
7fbc1067 CH |
209 | |
210 | int (*get_uuid)(struct super_block *sb, u8 *buf, u32 *len, u64 *offset); | |
211 | int (*map_blocks)(struct inode *inode, loff_t offset, | |
212 | u64 len, struct iomap *iomap, | |
213 | bool write, u32 *device_generation); | |
214 | int (*commit_blocks)(struct inode *inode, struct iomap *iomaps, | |
215 | int nr_iomaps, struct iattr *iattr); | |
a5694255 CH |
216 | }; |
217 | ||
711c7bf9 CG |
218 | extern int exportfs_encode_inode_fh(struct inode *inode, struct fid *fid, |
219 | int *max_len, struct inode *parent); | |
6e91ea2b CH |
220 | extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid, |
221 | int *max_len, int connectable); | |
222 | extern struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid, | |
d37065cd CH |
223 | int fh_len, int fileid_type, int (*acceptable)(void *, struct dentry *), |
224 | void *context); | |
225 | ||
2596110a CH |
226 | /* |
227 | * Generic helpers for filesystems. | |
228 | */ | |
229 | extern struct dentry *generic_fh_to_dentry(struct super_block *sb, | |
230 | struct fid *fid, int fh_len, int fh_type, | |
231 | struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen)); | |
232 | extern struct dentry *generic_fh_to_parent(struct super_block *sb, | |
233 | struct fid *fid, int fh_len, int fh_type, | |
234 | struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen)); | |
235 | ||
a5694255 | 236 | #endif /* LINUX_EXPORTFS_H */ |