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Christoph Hellwiga5694252007-07-17 04:04:28 -07001#ifndef LINUX_EXPORTFS_H
2#define LINUX_EXPORTFS_H 1
3
4#include <linux/types.h>
5
6struct dentry;
Christoph Hellwig25961102007-10-21 16:42:05 -07007struct inode;
Christoph Hellwiga5694252007-07-17 04:04:28 -07008struct super_block;
Christoph Hellwigd37065c2007-07-17 04:04:30 -07009struct vfsmount;
Christoph Hellwiga5694252007-07-17 04:04:28 -070010
Aneesh Kumar K.V990d6c22011-01-29 18:43:26 +053011/* limit the handle size to NFSv4 handle size now */
12#define MAX_HANDLE_SZ 128
13
Christoph Hellwig6e91ea22007-10-21 16:42:03 -070014/*
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,
Rasmus Rohde221e5832008-04-30 17:22:06 +020039
40 /*
David Woodhousee4464fa2008-08-20 14:58:23 +010041 * 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 /*
Rasmus Rohde221e5832008-04-30 17:22:06 +020062 * 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,
Ryusuke Konishi8e656fd2010-08-27 00:23:02 +090073
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,
Christoph Hellwig6e91ea22007-10-21 16:42:03 -070086};
87
88struct fid {
89 union {
90 struct {
91 u32 ino;
92 u32 gen;
93 u32 parent_ino;
94 u32 parent_gen;
95 } i32;
Rasmus Rohde221e5832008-04-30 17:22:06 +020096 struct {
97 u32 block;
98 u16 partref;
99 u16 parent_partref;
100 u32 generation;
101 u32 parent_block;
102 u32 parent_generation;
103 } udf;
Steven Whitehouse9078dc02008-04-08 13:12:52 +0100104 __u32 raw[0];
Christoph Hellwig6e91ea22007-10-21 16:42:03 -0700105 };
106};
Christoph Hellwiga5694252007-07-17 04:04:28 -0700107
108/**
109 * struct export_operations - for nfsd to communicate with file systems
Christoph Hellwiga5694252007-07-17 04:04:28 -0700110 * @encode_fh: encode a file handle fragment from a dentry
Marc Dionne9b89ca72008-03-14 13:11:29 +0000111 * @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
Christoph Hellwiga5694252007-07-17 04:04:28 -0700113 * @get_name: find the name for a given inode in a given directory
114 * @get_parent: find the parent of a given directory
Ben Myersf5019122010-02-17 14:05:11 -0600115 * @commit_metadata: commit metadata changes to stable storage
Christoph Hellwiga5694252007-07-17 04:04:28 -0700116 *
J. Bruce Fieldsdc7a0812009-10-27 14:41:35 -0400117 * See Documentation/filesystems/nfs/Exporting for details on how to use
Christoph Hellwige38f9812007-10-21 16:42:19 -0700118 * this interface correctly.
Christoph Hellwiga5694252007-07-17 04:04:28 -0700119 *
Christoph Hellwiga5694252007-07-17 04:04:28 -0700120 * 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
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300123 * file referred to by the &struct dentry @de. If the @connectable flag is
Christoph Hellwiga5694252007-07-17 04:04:28 -0700124 * 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
Aneesh Kumar K.V5fe0c232011-01-29 18:43:25 +0530127 * 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.
Christoph Hellwiga5694252007-07-17 04:04:28 -0700131 *
Christoph Hellwig25961102007-10-21 16:42:05 -0700132 * 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 *
Christoph Hellwiga5694252007-07-17 04:04:28 -0700147 * 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 *
Ben Myersf5019122010-02-17 14:05:11 -0600159 * commit_metadata:
160 * @commit_metadata should commit metadata changes to stable storage.
161 *
Christoph Hellwiga5694252007-07-17 04:04:28 -0700162 * 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 {
Christoph Hellwiga5694252007-07-17 04:04:28 -0700168 int (*encode_fh)(struct dentry *de, __u32 *fh, int *max_len,
169 int connectable);
Christoph Hellwig25961102007-10-21 16:42:05 -0700170 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);
Christoph Hellwiga5694252007-07-17 04:04:28 -0700174 int (*get_name)(struct dentry *parent, char *name,
175 struct dentry *child);
176 struct dentry * (*get_parent)(struct dentry *child);
Ben Myersf5019122010-02-17 14:05:11 -0600177 int (*commit_metadata)(struct inode *inode);
Christoph Hellwiga5694252007-07-17 04:04:28 -0700178};
179
Christoph Hellwig6e91ea22007-10-21 16:42:03 -0700180extern 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,
Christoph Hellwigd37065c2007-07-17 04:04:30 -0700183 int fh_len, int fileid_type, int (*acceptable)(void *, struct dentry *),
184 void *context);
185
Christoph Hellwig25961102007-10-21 16:42:05 -0700186/*
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
Christoph Hellwiga5694252007-07-17 04:04:28 -0700196#endif /* LINUX_EXPORTFS_H */