1 #ifndef LINUX_EXPORTFS_H
2 #define LINUX_EXPORTFS_H 1
4 #include <linux/types.h>
11 /* limit the handle size to NFSv4 handle size now */
12 #define MAX_HANDLE_SZ 128
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.
20 * The filesystem must not use the value '0' or '0xff'.
24 * The root, or export point, of the filesystem.
25 * (Never actually passed down to the filesystem.
30 * 32bit inode number, 32 bit generation number.
35 * 32bit inode number, 32 bit generation number,
36 * 32 bit parent directory inode number.
38 FILEID_INO32_GEN_PARENT = 2,
41 * 64 bit object ID, 64 bit root object ID,
42 * 32 bit generation number.
44 FILEID_BTRFS_WITHOUT_PARENT = 0x4d,
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.
51 FILEID_BTRFS_WITH_PARENT = 0x4e,
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.
59 FILEID_BTRFS_WITH_PARENT_ROOT = 0x4f,
62 * 32 bit block number, 16 bit partition reference,
63 * 16 bit unused, 32 bit generation number.
65 FILEID_UDF_WITHOUT_PARENT = 0x51,
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
72 FILEID_UDF_WITH_PARENT = 0x52,
75 * 64 bit checkpoint number, 64 bit inode number,
76 * 32 bit generation number.
78 FILEID_NILFS_WITHOUT_PARENT = 0x61,
81 * 64 bit checkpoint number, 64 bit inode number,
82 * 32 bit generation number, 32 bit parent generation.
83 * 64 bit parent inode number.
85 FILEID_NILFS_WITH_PARENT = 0x62,
102 u32 parent_generation;
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
117 * See Documentation/filesystems/nfs/Exporting for details on how to use
118 * this interface correctly.
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.
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
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.
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.
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.
160 * @commit_metadata should commit metadata changes to stable storage.
163 * get_parent is called with child->d_inode->i_mutex down
164 * get_name is not (which is possibly inconsistent)
167 struct export_operations {
168 int (*encode_fh)(struct dentry *de, __u32 *fh, int *max_len,
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);
180 extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid,
181 int *max_len, int connectable);
182 extern struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid,
183 int fh_len, int fileid_type, int (*acceptable)(void *, struct dentry *),
187 * Generic helpers for filesystems.
189 extern 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));
192 extern 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));
196 #endif /* LINUX_EXPORTFS_H */