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