1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef LINUX_EXPORTFS_H
3 #define LINUX_EXPORTFS_H 1
5 #include <linux/types.h>
14 /* limit the handle size to NFSv4 handle size now */
15 #define MAX_HANDLE_SZ 128
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.
23 * The filesystem must not use the value '0' or '0xff'.
27 * The root, or export point, of the filesystem.
28 * (Never actually passed down to the filesystem.
33 * 32bit inode number, 32 bit generation number.
38 * 32bit inode number, 32 bit generation number,
39 * 32 bit parent directory inode number.
41 FILEID_INO32_GEN_PARENT
= 2,
44 * 64 bit object ID, 64 bit root object ID,
45 * 32 bit generation number.
47 FILEID_BTRFS_WITHOUT_PARENT
= 0x4d,
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.
54 FILEID_BTRFS_WITH_PARENT
= 0x4e,
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.
62 FILEID_BTRFS_WITH_PARENT_ROOT
= 0x4f,
65 * 32 bit block number, 16 bit partition reference,
66 * 16 bit unused, 32 bit generation number.
68 FILEID_UDF_WITHOUT_PARENT
= 0x51,
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
75 FILEID_UDF_WITH_PARENT
= 0x52,
78 * 64 bit checkpoint number, 64 bit inode number,
79 * 32 bit generation number.
81 FILEID_NILFS_WITHOUT_PARENT
= 0x61,
84 * 64 bit checkpoint number, 64 bit inode number,
85 * 32 bit generation number, 32 bit parent generation.
86 * 64 bit parent inode number.
88 FILEID_NILFS_WITH_PARENT
= 0x62,
91 * 32 bit generation number, 40 bit i_pos.
93 FILEID_FAT_WITHOUT_PARENT
= 0x71,
96 * 32 bit generation number, 40 bit i_pos,
97 * 32 bit parent generation number, 40 bit parent i_pos
99 FILEID_FAT_WITH_PARENT
= 0x72,
102 * 64 bit inode number, 32 bit generation number.
104 FILEID_INO64_GEN
= 0x81,
107 * 64 bit inode number, 32 bit generation number,
108 * 64 bit parent inode number, 32 bit parent generation.
110 FILEID_INO64_GEN_PARENT
= 0x82,
113 * 128 bit child FID (struct lu_fid)
114 * 128 bit parent FID (struct lu_fid)
116 FILEID_LUSTRE
= 0x97,
119 * 64 bit inode number, 32 bit subvolume, 32 bit generation number:
121 FILEID_BCACHEFS_WITHOUT_PARENT
= 0xb1,
122 FILEID_BCACHEFS_WITH_PARENT
= 0xb2,
125 * 64 bit unique kernfs id
127 FILEID_KERNFS
= 0xfe,
130 * Filesystems must not use 0xff file ID.
132 FILEID_INVALID
= 0xff,
153 u32 parent_generation
;
155 DECLARE_FLEX_ARRAY(__u32
, raw
);
159 #define EXPORT_FH_CONNECTABLE 0x1 /* Encode file handle with parent */
160 #define EXPORT_FH_FID 0x2 /* File handle may be non-decodeable */
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
171 * See Documentation/filesystems/nfs/exporting.rst for details on how to use
172 * this interface correctly.
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.
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.
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.
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.
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.
215 * @commit_metadata should commit metadata changes to stable storage.
218 * get_parent is called with child->d_inode->i_mutex down
219 * get_name is not (which is possibly inconsistent)
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
);
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
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 */
253 * exportfs_lock_op_is_async() - export op supports async lock operation
254 * @export_ops: the nfs export operations to check
256 * Returns true if the nfs export_operations structure has
257 * EXPORT_OP_ASYNC_LOCK in their flags set
260 exportfs_lock_op_is_async(const struct export_operations
*export_ops
)
262 return export_ops
->flags
& EXPORT_OP_ASYNC_LOCK
;
265 extern int exportfs_encode_inode_fh(struct inode
*inode
, struct fid
*fid
,
266 int *max_len
, struct inode
*parent
,
268 extern int exportfs_encode_fh(struct dentry
*dentry
, struct fid
*fid
,
269 int *max_len
, int flags
);
271 static inline bool exportfs_can_encode_fid(const struct export_operations
*nop
)
273 return !nop
|| nop
->encode_fh
;
276 static inline bool exportfs_can_decode_fh(const struct export_operations
*nop
)
278 return nop
&& nop
->fh_to_dentry
;
281 static inline bool exportfs_can_encode_fh(const struct export_operations
*nop
,
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.
288 if (fh_flags
& EXPORT_FH_FID
)
289 return exportfs_can_encode_fid(nop
);
292 * If a decodeable file handle was requested, we need to make sure that
293 * filesystem can also decode file handles.
295 return exportfs_can_decode_fh(nop
);
298 static inline int exportfs_encode_fid(struct inode
*inode
, struct fid
*fid
,
301 return exportfs_encode_inode_fh(inode
, fid
, max_len
, NULL
,
305 extern struct dentry
*exportfs_decode_fh_raw(struct vfsmount
*mnt
,
306 struct fid
*fid
, int fh_len
,
308 int (*acceptable
)(void *, struct dentry
*),
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
*),
315 * Generic helpers for filesystems.
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
));
326 #endif /* LINUX_EXPORTFS_H */