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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
7struct dentry;
8struct iattr;
9struct inode;
10struct iomap;
11struct super_block;
12struct 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 */
25enum 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 * 128 bit child FID (struct lu_fid)
103 * 128 bit parent FID (struct lu_fid)
104 */
105 FILEID_LUSTRE = 0x97,
106
107 /*
108 * 64 bit unique kernfs id
109 */
110 FILEID_KERNFS = 0xfe,
111
112 /*
113 * Filesystems must not use 0xff file ID.
114 */
115 FILEID_INVALID = 0xff,
116};
117
118struct fid {
119 union {
120 struct {
121 u32 ino;
122 u32 gen;
123 u32 parent_ino;
124 u32 parent_gen;
125 } i32;
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;
134 __u32 raw[0];
135 };
136};
137
138/**
139 * struct export_operations - for nfsd to communicate with file systems
140 * @encode_fh: encode a file handle fragment from a dentry
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
143 * @get_name: find the name for a given inode in a given directory
144 * @get_parent: find the parent of a given directory
145 * @commit_metadata: commit metadata changes to stable storage
146 *
147 * See Documentation/filesystems/nfs/exporting.rst for details on how to use
148 * this interface correctly.
149 *
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
153 * file referred to by the &struct dentry @de. If the @connectable flag is
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
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.
161 *
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,
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.
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 *
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 %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 *
190 * commit_metadata:
191 * @commit_metadata should commit metadata changes to stable storage.
192 *
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
198struct export_operations {
199 int (*encode_fh)(struct inode *inode, __u32 *fh, int *max_len,
200 struct inode *parent);
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);
205 int (*get_name)(struct dentry *parent, char *name,
206 struct dentry *child);
207 struct dentry * (*get_parent)(struct dentry *child);
208 int (*commit_metadata)(struct inode *inode);
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);
216};
217
218extern int exportfs_encode_inode_fh(struct inode *inode, struct fid *fid,
219 int *max_len, struct inode *parent);
220extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid,
221 int *max_len, int connectable);
222extern struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid,
223 int fh_len, int fileid_type, int (*acceptable)(void *, struct dentry *),
224 void *context);
225
226/*
227 * Generic helpers for filesystems.
228 */
229extern 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));
232extern 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
236#endif /* LINUX_EXPORTFS_H */
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
7struct dentry;
8struct iattr;
9struct inode;
10struct iomap;
11struct super_block;
12struct 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 */
25enum 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
135struct 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#define EXPORT_FH_DIR_ONLY 0x4 /* Only decode file handle for a directory */
162
163/*
164 * Filesystems use only lower 8 bits of file_handle type for fid_type.
165 * name_to_handle_at() uses upper 16 bits of type as user flags to be
166 * interpreted by open_by_handle_at().
167 */
168#define FILEID_USER_FLAGS_MASK 0xffff0000
169#define FILEID_USER_FLAGS(type) ((type) & FILEID_USER_FLAGS_MASK)
170
171/* Flags supported in encoded handle_type that is exported to user */
172#define FILEID_IS_CONNECTABLE 0x10000
173#define FILEID_IS_DIR 0x20000
174#define FILEID_VALID_USER_FLAGS (FILEID_IS_CONNECTABLE | FILEID_IS_DIR)
175
176/**
177 * struct export_operations - for nfsd to communicate with file systems
178 * @encode_fh: encode a file handle fragment from a dentry
179 * @fh_to_dentry: find the implied object and get a dentry for it
180 * @fh_to_parent: find the implied object's parent and get a dentry for it
181 * @get_name: find the name for a given inode in a given directory
182 * @get_parent: find the parent of a given directory
183 * @commit_metadata: commit metadata changes to stable storage
184 *
185 * See Documentation/filesystems/nfs/exporting.rst for details on how to use
186 * this interface correctly.
187 *
188 * encode_fh:
189 * @encode_fh should store in the file handle fragment @fh (using at most
190 * @max_len bytes) information that can be used by @decode_fh to recover the
191 * file referred to by the &struct dentry @de. If @flag has CONNECTABLE bit
192 * set, the encode_fh() should store sufficient information so that a good
193 * attempt can be made to find not only the file but also it's place in the
194 * filesystem. This typically means storing a reference to de->d_parent in
195 * the filehandle fragment. encode_fh() should return the fileid_type on
196 * success and on error returns 255 (if the space needed to encode fh is
197 * greater than @max_len*4 bytes). On error @max_len contains the minimum
198 * size(in 4 byte unit) needed to encode the file handle.
199 *
200 * fh_to_dentry:
201 * @fh_to_dentry is given a &struct super_block (@sb) and a file handle
202 * fragment (@fh, @fh_len). It should return a &struct dentry which refers
203 * to the same file that the file handle fragment refers to. If it cannot,
204 * it should return a %NULL pointer if the file cannot be found, or an
205 * %ERR_PTR error code of %ENOMEM if a memory allocation failure occurred.
206 * Any other error code is treated like %NULL, and will cause an %ESTALE error
207 * for callers of exportfs_decode_fh().
208 * Any suitable dentry can be returned including, if necessary, a new dentry
209 * created with d_alloc_root. The caller can then find any other extant
210 * dentries by following the d_alias links.
211 *
212 * fh_to_parent:
213 * Same as @fh_to_dentry, except that it returns a pointer to the parent
214 * dentry if it was encoded into the filehandle fragment by @encode_fh.
215 *
216 * get_name:
217 * @get_name should find a name for the given @child in the given @parent
218 * directory. The name should be stored in the @name (with the
219 * understanding that it is already pointing to a %NAME_MAX+1 sized
220 * buffer. get_name() should return %0 on success, a negative error code
221 * or error. @get_name will be called without @parent->i_mutex held.
222 *
223 * get_parent:
224 * @get_parent should find the parent directory for the given @child which
225 * is also a directory. In the event that it cannot be found, or storage
226 * space cannot be allocated, a %ERR_PTR should be returned.
227 *
228 * commit_metadata:
229 * @commit_metadata should commit metadata changes to stable storage.
230 *
231 * Locking rules:
232 * get_parent is called with child->d_inode->i_mutex down
233 * get_name is not (which is possibly inconsistent)
234 */
235
236struct export_operations {
237 int (*encode_fh)(struct inode *inode, __u32 *fh, int *max_len,
238 struct inode *parent);
239 struct dentry * (*fh_to_dentry)(struct super_block *sb, struct fid *fid,
240 int fh_len, int fh_type);
241 struct dentry * (*fh_to_parent)(struct super_block *sb, struct fid *fid,
242 int fh_len, int fh_type);
243 int (*get_name)(struct dentry *parent, char *name,
244 struct dentry *child);
245 struct dentry * (*get_parent)(struct dentry *child);
246 int (*commit_metadata)(struct inode *inode);
247
248 int (*get_uuid)(struct super_block *sb, u8 *buf, u32 *len, u64 *offset);
249 int (*map_blocks)(struct inode *inode, loff_t offset,
250 u64 len, struct iomap *iomap,
251 bool write, u32 *device_generation);
252 int (*commit_blocks)(struct inode *inode, struct iomap *iomaps,
253 int nr_iomaps, struct iattr *iattr);
254#define EXPORT_OP_NOWCC (0x1) /* don't collect v3 wcc data */
255#define EXPORT_OP_NOSUBTREECHK (0x2) /* no subtree checking */
256#define EXPORT_OP_CLOSE_BEFORE_UNLINK (0x4) /* close files before unlink */
257#define EXPORT_OP_REMOTE_FS (0x8) /* Filesystem is remote */
258#define EXPORT_OP_NOATOMIC_ATTR (0x10) /* Filesystem cannot supply
259 atomic attribute updates
260 */
261#define EXPORT_OP_FLUSH_ON_CLOSE (0x20) /* fs flushes file data on close */
262#define EXPORT_OP_ASYNC_LOCK (0x40) /* fs can do async lock request */
263 unsigned long flags;
264};
265
266extern int exportfs_encode_inode_fh(struct inode *inode, struct fid *fid,
267 int *max_len, struct inode *parent,
268 int flags);
269extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid,
270 int *max_len, int flags);
271
272static inline bool exportfs_can_encode_fid(const struct export_operations *nop)
273{
274 return !nop || nop->encode_fh;
275}
276
277static inline bool exportfs_can_decode_fh(const struct export_operations *nop)
278{
279 return nop && nop->fh_to_dentry;
280}
281
282static inline bool exportfs_can_encode_fh(const struct export_operations *nop,
283 int fh_flags)
284{
285 /*
286 * If a non-decodeable file handle was requested, we only need to make
287 * sure that filesystem did not opt-out of encoding fid.
288 */
289 if (fh_flags & EXPORT_FH_FID)
290 return exportfs_can_encode_fid(nop);
291
292 /*
293 * If a decodeable file handle was requested, we need to make sure that
294 * filesystem can also decode file handles.
295 */
296 return exportfs_can_decode_fh(nop);
297}
298
299static inline int exportfs_encode_fid(struct inode *inode, struct fid *fid,
300 int *max_len)
301{
302 return exportfs_encode_inode_fh(inode, fid, max_len, NULL,
303 EXPORT_FH_FID);
304}
305
306extern struct dentry *exportfs_decode_fh_raw(struct vfsmount *mnt,
307 struct fid *fid, int fh_len,
308 int fileid_type,
309 unsigned int flags,
310 int (*acceptable)(void *, struct dentry *),
311 void *context);
312extern struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid,
313 int fh_len, int fileid_type, int (*acceptable)(void *, struct dentry *),
314 void *context);
315
316/*
317 * Generic helpers for filesystems.
318 */
319int generic_encode_ino32_fh(struct inode *inode, __u32 *fh, int *max_len,
320 struct inode *parent);
321struct dentry *generic_fh_to_dentry(struct super_block *sb,
322 struct fid *fid, int fh_len, int fh_type,
323 struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen));
324struct dentry *generic_fh_to_parent(struct super_block *sb,
325 struct fid *fid, int fh_len, int fh_type,
326 struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen));
327
328#endif /* LINUX_EXPORTFS_H */