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 * Filesystems must not use 0xff file ID. 101 */ 102 FILEID_INVALID = 0xff, 103 }; 104 105 struct fid { 106 union { 107 struct { 108 u32 ino; 109 u32 gen; 110 u32 parent_ino; 111 u32 parent_gen; 112 } i32; 113 struct { 114 u32 block; 115 u16 partref; 116 u16 parent_partref; 117 u32 generation; 118 u32 parent_block; 119 u32 parent_generation; 120 } udf; 121 __u32 raw[0]; 122 }; 123 }; 124 125 /** 126 * struct export_operations - for nfsd to communicate with file systems 127 * @encode_fh: encode a file handle fragment from a dentry 128 * @fh_to_dentry: find the implied object and get a dentry for it 129 * @fh_to_parent: find the implied object's parent and get a dentry for it 130 * @get_name: find the name for a given inode in a given directory 131 * @get_parent: find the parent of a given directory 132 * @commit_metadata: commit metadata changes to stable storage 133 * 134 * See Documentation/filesystems/nfs/Exporting for details on how to use 135 * this interface correctly. 136 * 137 * encode_fh: 138 * @encode_fh should store in the file handle fragment @fh (using at most 139 * @max_len bytes) information that can be used by @decode_fh to recover the 140 * file referred to by the &struct dentry @de. If the @connectable flag is 141 * set, the encode_fh() should store sufficient information so that a good 142 * attempt can be made to find not only the file but also it's place in the 143 * filesystem. This typically means storing a reference to de->d_parent in 144 * the filehandle fragment. encode_fh() should return the fileid_type on 145 * success and on error returns 255 (if the space needed to encode fh is 146 * greater than @max_len*4 bytes). On error @max_len contains the minimum 147 * size(in 4 byte unit) needed to encode the file handle. 148 * 149 * fh_to_dentry: 150 * @fh_to_dentry is given a &struct super_block (@sb) and a file handle 151 * fragment (@fh, @fh_len). It should return a &struct dentry which refers 152 * to the same file that the file handle fragment refers to. If it cannot, 153 * it should return a %NULL pointer if the file was found but no acceptable 154 * &dentries were available, or an %ERR_PTR error code indicating why it 155 * couldn't be found (e.g. %ENOENT or %ENOMEM). Any suitable dentry can be 156 * returned including, if necessary, a new dentry created with d_alloc_root. 157 * The caller can then find any other extant dentries by following the 158 * d_alias links. 159 * 160 * fh_to_parent: 161 * Same as @fh_to_dentry, except that it returns a pointer to the parent 162 * dentry if it was encoded into the filehandle fragment by @encode_fh. 163 * 164 * get_name: 165 * @get_name should find a name for the given @child in the given @parent 166 * directory. The name should be stored in the @name (with the 167 * understanding that it is already pointing to a a %NAME_MAX+1 sized 168 * buffer. get_name() should return %0 on success, a negative error code 169 * or error. @get_name will be called without @parent->i_mutex held. 170 * 171 * get_parent: 172 * @get_parent should find the parent directory for the given @child which 173 * is also a directory. In the event that it cannot be found, or storage 174 * space cannot be allocated, a %ERR_PTR should be returned. 175 * 176 * commit_metadata: 177 * @commit_metadata should commit metadata changes to stable storage. 178 * 179 * Locking rules: 180 * get_parent is called with child->d_inode->i_mutex down 181 * get_name is not (which is possibly inconsistent) 182 */ 183 184 /* types of block ranges for multipage write mappings. */ 185 #define IOMAP_HOLE 0x01 /* no blocks allocated, need allocation */ 186 #define IOMAP_DELALLOC 0x02 /* delayed allocation blocks */ 187 #define IOMAP_MAPPED 0x03 /* blocks allocated @blkno */ 188 #define IOMAP_UNWRITTEN 0x04 /* blocks allocated @blkno in unwritten state */ 189 190 #define IOMAP_NULL_BLOCK -1LL /* blkno is not valid */ 191 192 struct iomap { 193 sector_t blkno; /* first sector of mapping */ 194 loff_t offset; /* file offset of mapping, bytes */ 195 u64 length; /* length of mapping, bytes */ 196 int type; /* type of mapping */ 197 }; 198 199 struct export_operations { 200 int (*encode_fh)(struct inode *inode, __u32 *fh, int *max_len, 201 struct inode *parent); 202 struct dentry * (*fh_to_dentry)(struct super_block *sb, struct fid *fid, 203 int fh_len, int fh_type); 204 struct dentry * (*fh_to_parent)(struct super_block *sb, struct fid *fid, 205 int fh_len, int fh_type); 206 int (*get_name)(struct dentry *parent, char *name, 207 struct dentry *child); 208 struct dentry * (*get_parent)(struct dentry *child); 209 int (*commit_metadata)(struct inode *inode); 210 211 int (*get_uuid)(struct super_block *sb, u8 *buf, u32 *len, u64 *offset); 212 int (*map_blocks)(struct inode *inode, loff_t offset, 213 u64 len, struct iomap *iomap, 214 bool write, u32 *device_generation); 215 int (*commit_blocks)(struct inode *inode, struct iomap *iomaps, 216 int nr_iomaps, struct iattr *iattr); 217 }; 218 219 extern int exportfs_encode_inode_fh(struct inode *inode, struct fid *fid, 220 int *max_len, struct inode *parent); 221 extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid, 222 int *max_len, int connectable); 223 extern struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid, 224 int fh_len, int fileid_type, int (*acceptable)(void *, struct dentry *), 225 void *context); 226 227 /* 228 * Generic helpers for filesystems. 229 */ 230 extern struct dentry *generic_fh_to_dentry(struct super_block *sb, 231 struct fid *fid, int fh_len, int fh_type, 232 struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen)); 233 extern struct dentry *generic_fh_to_parent(struct super_block *sb, 234 struct fid *fid, int fh_len, int fh_type, 235 struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen)); 236 237 #endif /* LINUX_EXPORTFS_H */ 238