1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef LINUX_EXPORTFS_H |
3 | #define LINUX_EXPORTFS_H 1 |
4 | |
5 | #include <linux/types.h> |
6 | |
7 | struct dentry; |
8 | struct iattr; |
9 | struct inode; |
10 | struct iomap; |
11 | struct super_block; |
12 | struct vfsmount; |
13 | |
14 | /* limit the handle size to NFSv4 handle size now */ |
15 | #define MAX_HANDLE_SZ 128 |
16 | |
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, |
42 | |
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 | |
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, |
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, |
89 | |
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 | |
101 | /* |
102 | * 64 bit inode number, 32 bit generation number. |
103 | */ |
104 | FILEID_INO64_GEN = 0x81, |
105 | |
106 | /* |
107 | * 64 bit inode number, 32 bit generation number, |
108 | * 64 bit parent inode number, 32 bit parent generation. |
109 | */ |
110 | FILEID_INO64_GEN_PARENT = 0x82, |
111 | |
112 | /* |
113 | * 128 bit child FID (struct lu_fid) |
114 | * 128 bit parent FID (struct lu_fid) |
115 | */ |
116 | FILEID_LUSTRE = 0x97, |
117 | |
118 | /* |
119 | * 64 bit inode number, 32 bit subvolume, 32 bit generation number: |
120 | */ |
121 | FILEID_BCACHEFS_WITHOUT_PARENT = 0xb1, |
122 | FILEID_BCACHEFS_WITH_PARENT = 0xb2, |
123 | |
124 | /* |
125 | * 64 bit unique kernfs id |
126 | */ |
127 | FILEID_KERNFS = 0xfe, |
128 | |
129 | /* |
130 | * Filesystems must not use 0xff file ID. |
131 | */ |
132 | FILEID_INVALID = 0xff, |
133 | }; |
134 | |
135 | struct fid { |
136 | union { |
137 | struct { |
138 | u32 ino; |
139 | u32 gen; |
140 | u32 parent_ino; |
141 | u32 parent_gen; |
142 | } i32; |
143 | struct { |
144 | u64 ino; |
145 | u32 gen; |
146 | } __packed i64; |
147 | struct { |
148 | u32 block; |
149 | u16 partref; |
150 | u16 parent_partref; |
151 | u32 generation; |
152 | u32 parent_block; |
153 | u32 parent_generation; |
154 | } udf; |
155 | DECLARE_FLEX_ARRAY(__u32, raw); |
156 | }; |
157 | }; |
158 | |
159 | #define EXPORT_FH_CONNECTABLE 0x1 /* Encode file handle with parent */ |
160 | #define EXPORT_FH_FID 0x2 /* File handle may be non-decodeable */ |
161 | |
162 | /** |
163 | * struct export_operations - for nfsd to communicate with file systems |
164 | * @encode_fh: encode a file handle fragment from a dentry |
165 | * @fh_to_dentry: find the implied object and get a dentry for it |
166 | * @fh_to_parent: find the implied object's parent and get a dentry for it |
167 | * @get_name: find the name for a given inode in a given directory |
168 | * @get_parent: find the parent of a given directory |
169 | * @commit_metadata: commit metadata changes to stable storage |
170 | * |
171 | * See Documentation/filesystems/nfs/exporting.rst for details on how to use |
172 | * this interface correctly. |
173 | * |
174 | * encode_fh: |
175 | * @encode_fh should store in the file handle fragment @fh (using at most |
176 | * @max_len bytes) information that can be used by @decode_fh to recover the |
177 | * file referred to by the &struct dentry @de. If @flag has CONNECTABLE bit |
178 | * set, the encode_fh() should store sufficient information so that a good |
179 | * attempt can be made to find not only the file but also it's place in the |
180 | * filesystem. This typically means storing a reference to de->d_parent in |
181 | * the filehandle fragment. encode_fh() should return the fileid_type on |
182 | * success and on error returns 255 (if the space needed to encode fh is |
183 | * greater than @max_len*4 bytes). On error @max_len contains the minimum |
184 | * size(in 4 byte unit) needed to encode the file handle. |
185 | * |
186 | * fh_to_dentry: |
187 | * @fh_to_dentry is given a &struct super_block (@sb) and a file handle |
188 | * fragment (@fh, @fh_len). It should return a &struct dentry which refers |
189 | * to the same file that the file handle fragment refers to. If it cannot, |
190 | * it should return a %NULL pointer if the file cannot be found, or an |
191 | * %ERR_PTR error code of %ENOMEM if a memory allocation failure occurred. |
192 | * Any other error code is treated like %NULL, and will cause an %ESTALE error |
193 | * for callers of exportfs_decode_fh(). |
194 | * Any suitable dentry can be returned including, if necessary, a new dentry |
195 | * created with d_alloc_root. The caller can then find any other extant |
196 | * dentries by following the d_alias links. |
197 | * |
198 | * fh_to_parent: |
199 | * Same as @fh_to_dentry, except that it returns a pointer to the parent |
200 | * dentry if it was encoded into the filehandle fragment by @encode_fh. |
201 | * |
202 | * get_name: |
203 | * @get_name should find a name for the given @child in the given @parent |
204 | * directory. The name should be stored in the @name (with the |
205 | * understanding that it is already pointing to a %NAME_MAX+1 sized |
206 | * buffer. get_name() should return %0 on success, a negative error code |
207 | * or error. @get_name will be called without @parent->i_mutex held. |
208 | * |
209 | * get_parent: |
210 | * @get_parent should find the parent directory for the given @child which |
211 | * is also a directory. In the event that it cannot be found, or storage |
212 | * space cannot be allocated, a %ERR_PTR should be returned. |
213 | * |
214 | * commit_metadata: |
215 | * @commit_metadata should commit metadata changes to stable storage. |
216 | * |
217 | * Locking rules: |
218 | * get_parent is called with child->d_inode->i_mutex down |
219 | * get_name is not (which is possibly inconsistent) |
220 | */ |
221 | |
222 | struct export_operations { |
223 | int (*encode_fh)(struct inode *inode, __u32 *fh, int *max_len, |
224 | struct inode *parent); |
225 | struct dentry * (*fh_to_dentry)(struct super_block *sb, struct fid *fid, |
226 | int fh_len, int fh_type); |
227 | struct dentry * (*fh_to_parent)(struct super_block *sb, struct fid *fid, |
228 | int fh_len, int fh_type); |
229 | int (*get_name)(struct dentry *parent, char *name, |
230 | struct dentry *child); |
231 | struct dentry * (*get_parent)(struct dentry *child); |
232 | int (*commit_metadata)(struct inode *inode); |
233 | |
234 | int (*get_uuid)(struct super_block *sb, u8 *buf, u32 *len, u64 *offset); |
235 | int (*map_blocks)(struct inode *inode, loff_t offset, |
236 | u64 len, struct iomap *iomap, |
237 | bool write, u32 *device_generation); |
238 | int (*commit_blocks)(struct inode *inode, struct iomap *iomaps, |
239 | int nr_iomaps, struct iattr *iattr); |
240 | #define EXPORT_OP_NOWCC (0x1) /* don't collect v3 wcc data */ |
241 | #define EXPORT_OP_NOSUBTREECHK (0x2) /* no subtree checking */ |
242 | #define EXPORT_OP_CLOSE_BEFORE_UNLINK (0x4) /* close files before unlink */ |
243 | #define EXPORT_OP_REMOTE_FS (0x8) /* Filesystem is remote */ |
244 | #define EXPORT_OP_NOATOMIC_ATTR (0x10) /* Filesystem cannot supply |
245 | atomic attribute updates |
246 | */ |
247 | #define EXPORT_OP_FLUSH_ON_CLOSE (0x20) /* fs flushes file data on close */ |
248 | #define EXPORT_OP_ASYNC_LOCK (0x40) /* fs can do async lock request */ |
249 | unsigned long flags; |
250 | }; |
251 | |
252 | /** |
253 | * exportfs_lock_op_is_async() - export op supports async lock operation |
254 | * @export_ops: the nfs export operations to check |
255 | * |
256 | * Returns true if the nfs export_operations structure has |
257 | * EXPORT_OP_ASYNC_LOCK in their flags set |
258 | */ |
259 | static inline bool |
260 | exportfs_lock_op_is_async(const struct export_operations *export_ops) |
261 | { |
262 | return export_ops->flags & EXPORT_OP_ASYNC_LOCK; |
263 | } |
264 | |
265 | extern int exportfs_encode_inode_fh(struct inode *inode, struct fid *fid, |
266 | int *max_len, struct inode *parent, |
267 | int flags); |
268 | extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid, |
269 | int *max_len, int flags); |
270 | |
271 | static inline bool exportfs_can_encode_fid(const struct export_operations *nop) |
272 | { |
273 | return !nop || nop->encode_fh; |
274 | } |
275 | |
276 | static inline bool exportfs_can_decode_fh(const struct export_operations *nop) |
277 | { |
278 | return nop && nop->fh_to_dentry; |
279 | } |
280 | |
281 | static inline bool exportfs_can_encode_fh(const struct export_operations *nop, |
282 | int fh_flags) |
283 | { |
284 | /* |
285 | * If a non-decodeable file handle was requested, we only need to make |
286 | * sure that filesystem did not opt-out of encoding fid. |
287 | */ |
288 | if (fh_flags & EXPORT_FH_FID) |
289 | return exportfs_can_encode_fid(nop); |
290 | |
291 | /* |
292 | * If a decodeable file handle was requested, we need to make sure that |
293 | * filesystem can also decode file handles. |
294 | */ |
295 | return exportfs_can_decode_fh(nop); |
296 | } |
297 | |
298 | static inline int exportfs_encode_fid(struct inode *inode, struct fid *fid, |
299 | int *max_len) |
300 | { |
301 | return exportfs_encode_inode_fh(inode, fid, max_len, NULL, |
302 | EXPORT_FH_FID); |
303 | } |
304 | |
305 | extern struct dentry *exportfs_decode_fh_raw(struct vfsmount *mnt, |
306 | struct fid *fid, int fh_len, |
307 | int fileid_type, |
308 | int (*acceptable)(void *, struct dentry *), |
309 | void *context); |
310 | extern struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid, |
311 | int fh_len, int fileid_type, int (*acceptable)(void *, struct dentry *), |
312 | void *context); |
313 | |
314 | /* |
315 | * Generic helpers for filesystems. |
316 | */ |
317 | int generic_encode_ino32_fh(struct inode *inode, __u32 *fh, int *max_len, |
318 | struct inode *parent); |
319 | struct dentry *generic_fh_to_dentry(struct super_block *sb, |
320 | struct fid *fid, int fh_len, int fh_type, |
321 | struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen)); |
322 | struct dentry *generic_fh_to_parent(struct super_block *sb, |
323 | struct fid *fid, int fh_len, int fh_type, |
324 | struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen)); |
325 | |
326 | #endif /* LINUX_EXPORTFS_H */ |
327 | |