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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#ifndef LINUX_EXPORTFS_H
2#define LINUX_EXPORTFS_H 1
3
4#include <linux/types.h>
5
6struct dentry;
7struct inode;
8struct super_block;
9struct vfsmount;
10
11/* limit the handle size to NFSv4 handle size now */
12#define MAX_HANDLE_SZ 128
13
14/*
15 * The fileid_type identifies how the file within the filesystem is encoded.
16 * In theory this is freely set and parsed by the filesystem, but we try to
17 * stick to conventions so we can share some generic code and don't confuse
18 * sniffers like ethereal/wireshark.
19 *
20 * The filesystem must not use the value '0' or '0xff'.
21 */
22enum fid_type {
23 /*
24 * The root, or export point, of the filesystem.
25 * (Never actually passed down to the filesystem.
26 */
27 FILEID_ROOT = 0,
28
29 /*
30 * 32bit inode number, 32 bit generation number.
31 */
32 FILEID_INO32_GEN = 1,
33
34 /*
35 * 32bit inode number, 32 bit generation number,
36 * 32 bit parent directory inode number.
37 */
38 FILEID_INO32_GEN_PARENT = 2,
39
40 /*
41 * 64 bit object ID, 64 bit root object ID,
42 * 32 bit generation number.
43 */
44 FILEID_BTRFS_WITHOUT_PARENT = 0x4d,
45
46 /*
47 * 64 bit object ID, 64 bit root object ID,
48 * 32 bit generation number,
49 * 64 bit parent object ID, 32 bit parent generation.
50 */
51 FILEID_BTRFS_WITH_PARENT = 0x4e,
52
53 /*
54 * 64 bit object ID, 64 bit root object ID,
55 * 32 bit generation number,
56 * 64 bit parent object ID, 32 bit parent generation,
57 * 64 bit parent root object ID.
58 */
59 FILEID_BTRFS_WITH_PARENT_ROOT = 0x4f,
60
61 /*
62 * 32 bit block number, 16 bit partition reference,
63 * 16 bit unused, 32 bit generation number.
64 */
65 FILEID_UDF_WITHOUT_PARENT = 0x51,
66
67 /*
68 * 32 bit block number, 16 bit partition reference,
69 * 16 bit unused, 32 bit generation number,
70 * 32 bit parent block number, 32 bit parent generation number
71 */
72 FILEID_UDF_WITH_PARENT = 0x52,
73
74 /*
75 * 64 bit checkpoint number, 64 bit inode number,
76 * 32 bit generation number.
77 */
78 FILEID_NILFS_WITHOUT_PARENT = 0x61,
79
80 /*
81 * 64 bit checkpoint number, 64 bit inode number,
82 * 32 bit generation number, 32 bit parent generation.
83 * 64 bit parent inode number.
84 */
85 FILEID_NILFS_WITH_PARENT = 0x62,
86};
87
88struct fid {
89 union {
90 struct {
91 u32 ino;
92 u32 gen;
93 u32 parent_ino;
94 u32 parent_gen;
95 } i32;
96 struct {
97 u32 block;
98 u16 partref;
99 u16 parent_partref;
100 u32 generation;
101 u32 parent_block;
102 u32 parent_generation;
103 } udf;
104 __u32 raw[0];
105 };
106};
107
108/**
109 * struct export_operations - for nfsd to communicate with file systems
110 * @encode_fh: encode a file handle fragment from a dentry
111 * @fh_to_dentry: find the implied object and get a dentry for it
112 * @fh_to_parent: find the implied object's parent and get a dentry for it
113 * @get_name: find the name for a given inode in a given directory
114 * @get_parent: find the parent of a given directory
115 * @commit_metadata: commit metadata changes to stable storage
116 *
117 * See Documentation/filesystems/nfs/Exporting for details on how to use
118 * this interface correctly.
119 *
120 * encode_fh:
121 * @encode_fh should store in the file handle fragment @fh (using at most
122 * @max_len bytes) information that can be used by @decode_fh to recover the
123 * file referred to by the &struct dentry @de. If the @connectable flag is
124 * set, the encode_fh() should store sufficient information so that a good
125 * attempt can be made to find not only the file but also it's place in the
126 * filesystem. This typically means storing a reference to de->d_parent in
127 * the filehandle fragment. encode_fh() should return the fileid_type on
128 * success and on error returns 255 (if the space needed to encode fh is
129 * greater than @max_len*4 bytes). On error @max_len contains the minimum
130 * size(in 4 byte unit) needed to encode the file handle.
131 *
132 * fh_to_dentry:
133 * @fh_to_dentry is given a &struct super_block (@sb) and a file handle
134 * fragment (@fh, @fh_len). It should return a &struct dentry which refers
135 * to the same file that the file handle fragment refers to. If it cannot,
136 * it should return a %NULL pointer if the file was found but no acceptable
137 * &dentries were available, or an %ERR_PTR error code indicating why it
138 * couldn't be found (e.g. %ENOENT or %ENOMEM). Any suitable dentry can be
139 * returned including, if necessary, a new dentry created with d_alloc_root.
140 * The caller can then find any other extant dentries by following the
141 * d_alias links.
142 *
143 * fh_to_parent:
144 * Same as @fh_to_dentry, except that it returns a pointer to the parent
145 * dentry if it was encoded into the filehandle fragment by @encode_fh.
146 *
147 * get_name:
148 * @get_name should find a name for the given @child in the given @parent
149 * directory. The name should be stored in the @name (with the
150 * understanding that it is already pointing to a a %NAME_MAX+1 sized
151 * buffer. get_name() should return %0 on success, a negative error code
152 * or error. @get_name will be called without @parent->i_mutex held.
153 *
154 * get_parent:
155 * @get_parent should find the parent directory for the given @child which
156 * is also a directory. In the event that it cannot be found, or storage
157 * space cannot be allocated, a %ERR_PTR should be returned.
158 *
159 * commit_metadata:
160 * @commit_metadata should commit metadata changes to stable storage.
161 *
162 * Locking rules:
163 * get_parent is called with child->d_inode->i_mutex down
164 * get_name is not (which is possibly inconsistent)
165 */
166
167struct export_operations {
168 int (*encode_fh)(struct inode *inode, __u32 *fh, int *max_len,
169 struct inode *parent);
170 struct dentry * (*fh_to_dentry)(struct super_block *sb, struct fid *fid,
171 int fh_len, int fh_type);
172 struct dentry * (*fh_to_parent)(struct super_block *sb, struct fid *fid,
173 int fh_len, int fh_type);
174 int (*get_name)(struct dentry *parent, char *name,
175 struct dentry *child);
176 struct dentry * (*get_parent)(struct dentry *child);
177 int (*commit_metadata)(struct inode *inode);
178};
179
180extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid,
181 int *max_len, int connectable);
182extern struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid,
183 int fh_len, int fileid_type, int (*acceptable)(void *, struct dentry *),
184 void *context);
185
186/*
187 * Generic helpers for filesystems.
188 */
189extern struct dentry *generic_fh_to_dentry(struct super_block *sb,
190 struct fid *fid, int fh_len, int fh_type,
191 struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen));
192extern struct dentry *generic_fh_to_parent(struct super_block *sb,
193 struct fid *fid, int fh_len, int fh_type,
194 struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen));
195
196#endif /* LINUX_EXPORTFS_H */