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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 super_block;
10 struct vfsmount;
11
12 /* limit the handle size to NFSv4 handle size now */
13 #define MAX_HANDLE_SZ 128
14
15 /*
16 * The fileid_type identifies how the file within the filesystem is encoded.
17 * In theory this is freely set and parsed by the filesystem, but we try to
18 * stick to conventions so we can share some generic code and don't confuse
19 * sniffers like ethereal/wireshark.
20 *
21 * The filesystem must not use the value '0' or '0xff'.
22 */
23 enum fid_type {
24 /*
25 * The root, or export point, of the filesystem.
26 * (Never actually passed down to the filesystem.
27 */
28 FILEID_ROOT = 0,
29
30 /*
31 * 32bit inode number, 32 bit generation number.
32 */
33 FILEID_INO32_GEN = 1,
34
35 /*
36 * 32bit inode number, 32 bit generation number,
37 * 32 bit parent directory inode number.
38 */
39 FILEID_INO32_GEN_PARENT = 2,
40
41 /*
42 * 64 bit object ID, 64 bit root object ID,
43 * 32 bit generation number.
44 */
45 FILEID_BTRFS_WITHOUT_PARENT = 0x4d,
46
47 /*
48 * 64 bit object ID, 64 bit root object ID,
49 * 32 bit generation number,
50 * 64 bit parent object ID, 32 bit parent generation.
51 */
52 FILEID_BTRFS_WITH_PARENT = 0x4e,
53
54 /*
55 * 64 bit object ID, 64 bit root object ID,
56 * 32 bit generation number,
57 * 64 bit parent object ID, 32 bit parent generation,
58 * 64 bit parent root object ID.
59 */
60 FILEID_BTRFS_WITH_PARENT_ROOT = 0x4f,
61
62 /*
63 * 32 bit block number, 16 bit partition reference,
64 * 16 bit unused, 32 bit generation number.
65 */
66 FILEID_UDF_WITHOUT_PARENT = 0x51,
67
68 /*
69 * 32 bit block number, 16 bit partition reference,
70 * 16 bit unused, 32 bit generation number,
71 * 32 bit parent block number, 32 bit parent generation number
72 */
73 FILEID_UDF_WITH_PARENT = 0x52,
74
75 /*
76 * 64 bit checkpoint number, 64 bit inode number,
77 * 32 bit generation number.
78 */
79 FILEID_NILFS_WITHOUT_PARENT = 0x61,
80
81 /*
82 * 64 bit checkpoint number, 64 bit inode number,
83 * 32 bit generation number, 32 bit parent generation.
84 * 64 bit parent inode number.
85 */
86 FILEID_NILFS_WITH_PARENT = 0x62,
87
88 /*
89 * 32 bit generation number, 40 bit i_pos.
90 */
91 FILEID_FAT_WITHOUT_PARENT = 0x71,
92
93 /*
94 * 32 bit generation number, 40 bit i_pos,
95 * 32 bit parent generation number, 40 bit parent i_pos
96 */
97 FILEID_FAT_WITH_PARENT = 0x72,
98
99 /*
100 * 128 bit child FID (struct lu_fid)
101 * 128 bit parent FID (struct lu_fid)
102 */
103 FILEID_LUSTRE = 0x97,
104
105 /*
106 * Filesystems must not use 0xff file ID.
107 */
108 FILEID_INVALID = 0xff,
109 };
110
111 struct fid {
112 union {
113 struct {
114 u32 ino;
115 u32 gen;
116 u32 parent_ino;
117 u32 parent_gen;
118 } i32;
119 struct {
120 u32 block;
121 u16 partref;
122 u16 parent_partref;
123 u32 generation;
124 u32 parent_block;
125 u32 parent_generation;
126 } udf;
127 __u32 raw[0];
128 };
129 };
130
131 /**
132 * struct export_operations - for nfsd to communicate with file systems
133 * @encode_fh: encode a file handle fragment from a dentry
134 * @fh_to_dentry: find the implied object and get a dentry for it
135 * @fh_to_parent: find the implied object's parent and get a dentry for it
136 * @get_name: find the name for a given inode in a given directory
137 * @get_parent: find the parent of a given directory
138 * @commit_metadata: commit metadata changes to stable storage
139 *
140 * See Documentation/filesystems/nfs/Exporting for details on how to use
141 * this interface correctly.
142 *
143 * encode_fh:
144 * @encode_fh should store in the file handle fragment @fh (using at most
145 * @max_len bytes) information that can be used by @decode_fh to recover the
146 * file referred to by the &struct dentry @de. If the @connectable flag is
147 * set, the encode_fh() should store sufficient information so that a good
148 * attempt can be made to find not only the file but also it's place in the
149 * filesystem. This typically means storing a reference to de->d_parent in
150 * the filehandle fragment. encode_fh() should return the fileid_type on
151 * success and on error returns 255 (if the space needed to encode fh is
152 * greater than @max_len*4 bytes). On error @max_len contains the minimum
153 * size(in 4 byte unit) needed to encode the file handle.
154 *
155 * fh_to_dentry:
156 * @fh_to_dentry is given a &struct super_block (@sb) and a file handle
157 * fragment (@fh, @fh_len). It should return a &struct dentry which refers
158 * to the same file that the file handle fragment refers to. If it cannot,
159 * it should return a %NULL pointer if the file was found but no acceptable
160 * &dentries were available, or an %ERR_PTR error code indicating why it
161 * couldn't be found (e.g. %ENOENT or %ENOMEM). Any suitable dentry can be
162 * returned including, if necessary, a new dentry created with d_alloc_root.
163 * The caller can then find any other extant dentries by following the
164 * d_alias links.
165 *
166 * fh_to_parent:
167 * Same as @fh_to_dentry, except that it returns a pointer to the parent
168 * dentry if it was encoded into the filehandle fragment by @encode_fh.
169 *
170 * get_name:
171 * @get_name should find a name for the given @child in the given @parent
172 * directory. The name should be stored in the @name (with the
173 * understanding that it is already pointing to a a %NAME_MAX+1 sized
174 * buffer. get_name() should return %0 on success, a negative error code
175 * or error. @get_name will be called without @parent->i_mutex held.
176 *
177 * get_parent:
178 * @get_parent should find the parent directory for the given @child which
179 * is also a directory. In the event that it cannot be found, or storage
180 * space cannot be allocated, a %ERR_PTR should be returned.
181 *
182 * commit_metadata:
183 * @commit_metadata should commit metadata changes to stable storage.
184 *
185 * Locking rules:
186 * get_parent is called with child->d_inode->i_mutex down
187 * get_name is not (which is possibly inconsistent)
188 */
189
190 /* types of block ranges for multipage write mappings. */
191 #define IOMAP_HOLE 0x01 /* no blocks allocated, need allocation */
192 #define IOMAP_DELALLOC 0x02 /* delayed allocation blocks */
193 #define IOMAP_MAPPED 0x03 /* blocks allocated @blkno */
194 #define IOMAP_UNWRITTEN 0x04 /* blocks allocated @blkno in unwritten state */
195
196 #define IOMAP_NULL_BLOCK -1LL /* blkno is not valid */
197
198 struct iomap {
199 sector_t blkno; /* first sector of mapping */
200 loff_t offset; /* file offset of mapping, bytes */
201 u64 length; /* length of mapping, bytes */
202 int type; /* type of mapping */
203 };
204
205 struct export_operations {
206 int (*encode_fh)(struct inode *inode, __u32 *fh, int *max_len,
207 struct inode *parent);
208 struct dentry * (*fh_to_dentry)(struct super_block *sb, struct fid *fid,
209 int fh_len, int fh_type);
210 struct dentry * (*fh_to_parent)(struct super_block *sb, struct fid *fid,
211 int fh_len, int fh_type);
212 int (*get_name)(struct dentry *parent, char *name,
213 struct dentry *child);
214 struct dentry * (*get_parent)(struct dentry *child);
215 int (*commit_metadata)(struct inode *inode);
216
217 int (*get_uuid)(struct super_block *sb, u8 *buf, u32 *len, u64 *offset);
218 int (*map_blocks)(struct inode *inode, loff_t offset,
219 u64 len, struct iomap *iomap,
220 bool write, u32 *device_generation);
221 int (*commit_blocks)(struct inode *inode, struct iomap *iomaps,
222 int nr_iomaps, struct iattr *iattr);
223 };
224
225 extern int exportfs_encode_inode_fh(struct inode *inode, struct fid *fid,
226 int *max_len, struct inode *parent);
227 extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid,
228 int *max_len, int connectable);
229 extern struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid,
230 int fh_len, int fileid_type, int (*acceptable)(void *, struct dentry *),
231 void *context);
232
233 /*
234 * Generic helpers for filesystems.
235 */
236 extern struct dentry *generic_fh_to_dentry(struct super_block *sb,
237 struct fid *fid, int fh_len, int fh_type,
238 struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen));
239 extern struct dentry *generic_fh_to_parent(struct super_block *sb,
240 struct fid *fid, int fh_len, int fh_type,
241 struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen));
242
243 #endif /* LINUX_EXPORTFS_H */