[linux-2.6-block.git] / include / linux / exportfs.h

#ifndef LINUX_EXPORTFS_H
#define LINUX_EXPORTFS_H 1

#include <linux/types.h>

struct dentry;
struct iattr;
struct inode;
struct iomap;
struct super_block;
struct vfsmount;

/* limit the handle size to NFSv4 handle size now */
#define MAX_HANDLE_SZ 128

/*
 * The fileid_type identifies how the file within the filesystem is encoded.
 * In theory this is freely set and parsed by the filesystem, but we try to
 * stick to conventions so we can share some generic code and don't confuse
 * sniffers like ethereal/wireshark.
 *
 * The filesystem must not use the value '0' or '0xff'.
 */
enum fid_type {
	/*
	 * The root, or export point, of the filesystem.
	 * (Never actually passed down to the filesystem.
	 */
	FILEID_ROOT = 0,

	/*
	 * 32bit inode number, 32 bit generation number.
	 */
	FILEID_INO32_GEN = 1,

	/*
	 * 32bit inode number, 32 bit generation number,
	 * 32 bit parent directory inode number.
	 */
	FILEID_INO32_GEN_PARENT = 2,

	/*
	 * 64 bit object ID, 64 bit root object ID,
	 * 32 bit generation number.
	 */
	FILEID_BTRFS_WITHOUT_PARENT = 0x4d,

	/*
	 * 64 bit object ID, 64 bit root object ID,
	 * 32 bit generation number,
	 * 64 bit parent object ID, 32 bit parent generation.
	 */
	FILEID_BTRFS_WITH_PARENT = 0x4e,

	/*
	 * 64 bit object ID, 64 bit root object ID,
	 * 32 bit generation number,
	 * 64 bit parent object ID, 32 bit parent generation,
	 * 64 bit parent root object ID.
	 */
	FILEID_BTRFS_WITH_PARENT_ROOT = 0x4f,

	/*
	 * 32 bit block number, 16 bit partition reference,
	 * 16 bit unused, 32 bit generation number.
	 */
	FILEID_UDF_WITHOUT_PARENT = 0x51,

	/*
	 * 32 bit block number, 16 bit partition reference,
	 * 16 bit unused, 32 bit generation number,
	 * 32 bit parent block number, 32 bit parent generation number
	 */
	FILEID_UDF_WITH_PARENT = 0x52,

	/*
	 * 64 bit checkpoint number, 64 bit inode number,
	 * 32 bit generation number.
	 */
	FILEID_NILFS_WITHOUT_PARENT = 0x61,

	/*
	 * 64 bit checkpoint number, 64 bit inode number,
	 * 32 bit generation number, 32 bit parent generation.
	 * 64 bit parent inode number.
	 */
	FILEID_NILFS_WITH_PARENT = 0x62,

	/*
	 * 32 bit generation number, 40 bit i_pos.
	 */
	FILEID_FAT_WITHOUT_PARENT = 0x71,

	/*
	 * 32 bit generation number, 40 bit i_pos,
	 * 32 bit parent generation number, 40 bit parent i_pos
	 */
	FILEID_FAT_WITH_PARENT = 0x72,

	/*
	 * 128 bit child FID (struct lu_fid)
	 * 128 bit parent FID (struct lu_fid)
	 */
	FILEID_LUSTRE = 0x97,

	/*
	 * Filesystems must not use 0xff file ID.
	 */
	FILEID_INVALID = 0xff,
};

struct fid {
	union {
		struct {
			u32 ino;
			u32 gen;
			u32 parent_ino;
			u32 parent_gen;
		} i32;
 		struct {
 			u32 block;
 			u16 partref;
 			u16 parent_partref;
 			u32 generation;
 			u32 parent_block;
 			u32 parent_generation;
 		} udf;
		__u32 raw[0];
	};
};

/**
 * struct export_operations - for nfsd to communicate with file systems
 * @encode_fh:      encode a file handle fragment from a dentry
 * @fh_to_dentry:   find the implied object and get a dentry for it
 * @fh_to_parent:   find the implied object's parent and get a dentry for it
 * @get_name:       find the name for a given inode in a given directory
 * @get_parent:     find the parent of a given directory
 * @commit_metadata: commit metadata changes to stable storage
 *
 * See Documentation/filesystems/nfs/Exporting for details on how to use
 * this interface correctly.
 *
 * encode_fh:
 *    @encode_fh should store in the file handle fragment @fh (using at most
 *    @max_len bytes) information that can be used by @decode_fh to recover the
 *    file referred to by the &struct dentry @de.  If the @connectable flag is
 *    set, the encode_fh() should store sufficient information so that a good
 *    attempt can be made to find not only the file but also it's place in the
 *    filesystem.   This typically means storing a reference to de->d_parent in
 *    the filehandle fragment.  encode_fh() should return the fileid_type on
 *    success and on error returns 255 (if the space needed to encode fh is
 *    greater than @max_len*4 bytes). On error @max_len contains the minimum
 *    size(in 4 byte unit) needed to encode the file handle.
 *
 * fh_to_dentry:
 *    @fh_to_dentry is given a &struct super_block (@sb) and a file handle
 *    fragment (@fh, @fh_len). It should return a &struct dentry which refers
 *    to the same file that the file handle fragment refers to.  If it cannot,
 *    it should return a %NULL pointer if the file cannot be found, or an
 *    %ERR_PTR error code of %ENOMEM if a memory allocation failure occurred.
 *    Any other error code is treated like %NULL, and will cause an %ESTALE error
 *    for callers of exportfs_decode_fh().
 *    Any suitable dentry can be returned including, if necessary, a new dentry
 *    created with d_alloc_root.  The caller can then find any other extant
 *    dentries by following the d_alias links.
 *
 * fh_to_parent:
 *    Same as @fh_to_dentry, except that it returns a pointer to the parent
 *    dentry if it was encoded into the filehandle fragment by @encode_fh.
 *
 * get_name:
 *    @get_name should find a name for the given @child in the given @parent
 *    directory.  The name should be stored in the @name (with the
 *    understanding that it is already pointing to a a %NAME_MAX+1 sized
 *    buffer.   get_name() should return %0 on success, a negative error code
 *    or error.  @get_name will be called without @parent->i_mutex held.
 *
 * get_parent:
 *    @get_parent should find the parent directory for the given @child which
 *    is also a directory.  In the event that it cannot be found, or storage
 *    space cannot be allocated, a %ERR_PTR should be returned.
 *
 * commit_metadata:
 *    @commit_metadata should commit metadata changes to stable storage.
 *
 * Locking rules:
 *    get_parent is called with child->d_inode->i_mutex down
 *    get_name is not (which is possibly inconsistent)
 */

struct export_operations {
	int (*encode_fh)(struct inode *inode, __u32 *fh, int *max_len,
			struct inode *parent);
	struct dentry * (*fh_to_dentry)(struct super_block *sb, struct fid *fid,
			int fh_len, int fh_type);
	struct dentry * (*fh_to_parent)(struct super_block *sb, struct fid *fid,
			int fh_len, int fh_type);
	int (*get_name)(struct dentry *parent, char *name,
			struct dentry *child);
	struct dentry * (*get_parent)(struct dentry *child);
	int (*commit_metadata)(struct inode *inode);

	int (*get_uuid)(struct super_block *sb, u8 *buf, u32 *len, u64 *offset);
	int (*map_blocks)(struct inode *inode, loff_t offset,
			  u64 len, struct iomap *iomap,
			  bool write, u32 *device_generation);
	int (*commit_blocks)(struct inode *inode, struct iomap *iomaps,
			     int nr_iomaps, struct iattr *iattr);
};

extern int exportfs_encode_inode_fh(struct inode *inode, struct fid *fid,
				    int *max_len, struct inode *parent);
extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid,
	int *max_len, int connectable);
extern struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid,
	int fh_len, int fileid_type, int (*acceptable)(void *, struct dentry *),
	void *context);

/*
 * Generic helpers for filesystems.
 */
extern struct dentry *generic_fh_to_dentry(struct super_block *sb,
	struct fid *fid, int fh_len, int fh_type,
	struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen));
extern struct dentry *generic_fh_to_parent(struct super_block *sb,
	struct fid *fid, int fh_len, int fh_type,
	struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen));

#endif /* LINUX_EXPORTFS_H */
Commit	Line	Data
a5694255 CH	1	#ifndef LINUX_EXPORTFS_H
	2	#define LINUX_EXPORTFS_H 1
	3
	4	#include <linux/types.h>
	5
	6	struct dentry;
7fbc1067	7	struct iattr;
2596110a	8	struct inode;
199a31c6	9	struct iomap;
a5694255	10	struct super_block;
d37065cd	11	struct vfsmount;
a5694255	12
990d6c2d AK	13	/* limit the handle size to NFSv4 handle size now */
	14	#define MAX_HANDLE_SZ 128
	15
6e91ea2b CH	16	/*
	17	* The fileid_type identifies how the file within the filesystem is encoded.
	18	* In theory this is freely set and parsed by the filesystem, but we try to
	19	* stick to conventions so we can share some generic code and don't confuse
	20	* sniffers like ethereal/wireshark.
	21	*
	22	* The filesystem must not use the value '0' or '0xff'.
	23	*/
	24	enum fid_type {
	25	/*
	26	* The root, or export point, of the filesystem.
	27	* (Never actually passed down to the filesystem.
	28	*/
	29	FILEID_ROOT = 0,
	30
	31	/*
	32	* 32bit inode number, 32 bit generation number.
	33	*/
	34	FILEID_INO32_GEN = 1,
	35
	36	/*
	37	* 32bit inode number, 32 bit generation number,
	38	* 32 bit parent directory inode number.
	39	*/
	40	FILEID_INO32_GEN_PARENT = 2,
221e583a	41
e4464fac DW	42	/*
	43	* 64 bit object ID, 64 bit root object ID,
	44	* 32 bit generation number.
	45	*/
	46	FILEID_BTRFS_WITHOUT_PARENT = 0x4d,
	47
	48	/*
	49	* 64 bit object ID, 64 bit root object ID,
	50	* 32 bit generation number,
	51	* 64 bit parent object ID, 32 bit parent generation.
	52	*/
	53	FILEID_BTRFS_WITH_PARENT = 0x4e,
	54
	55	/*
	56	* 64 bit object ID, 64 bit root object ID,
	57	* 32 bit generation number,
	58	* 64 bit parent object ID, 32 bit parent generation,
	59	* 64 bit parent root object ID.
	60	*/
	61	FILEID_BTRFS_WITH_PARENT_ROOT = 0x4f,
	62
221e583a RR	63	/*
	64	* 32 bit block number, 16 bit partition reference,
	65	* 16 bit unused, 32 bit generation number.
	66	*/
	67	FILEID_UDF_WITHOUT_PARENT = 0x51,
	68
	69	/*
	70	* 32 bit block number, 16 bit partition reference,
	71	* 16 bit unused, 32 bit generation number,
	72	* 32 bit parent block number, 32 bit parent generation number
	73	*/
	74	FILEID_UDF_WITH_PARENT = 0x52,
8e656fd5 RK	75
	76	/*
	77	* 64 bit checkpoint number, 64 bit inode number,
	78	* 32 bit generation number.
	79	*/
	80	FILEID_NILFS_WITHOUT_PARENT = 0x61,
	81
	82	/*
	83	* 64 bit checkpoint number, 64 bit inode number,
	84	* 32 bit generation number, 32 bit parent generation.
	85	* 64 bit parent inode number.
	86	*/
	87	FILEID_NILFS_WITH_PARENT = 0x62,
216b6cbd	88
ea3983ac NJ	89	/*
	90	* 32 bit generation number, 40 bit i_pos.
	91	*/
	92	FILEID_FAT_WITHOUT_PARENT = 0x71,
	93
	94	/*
	95	* 32 bit generation number, 40 bit i_pos,
	96	* 32 bit parent generation number, 40 bit parent i_pos
	97	*/
	98	FILEID_FAT_WITH_PARENT = 0x72,
	99
cb776592 DE	100	/*
	101	* 128 bit child FID (struct lu_fid)
	102	* 128 bit parent FID (struct lu_fid)
	103	*/
	104	FILEID_LUSTRE = 0x97,
	105
216b6cbd NJ	106	/*
	107	* Filesystems must not use 0xff file ID.
	108	*/
	109	FILEID_INVALID = 0xff,
6e91ea2b CH	110	};
	111
	112	struct fid {
	113	union {
	114	struct {
	115	u32 ino;
	116	u32 gen;
	117	u32 parent_ino;
	118	u32 parent_gen;
	119	} i32;
221e583a RR	120	struct {
	121	u32 block;
	122	u16 partref;
	123	u16 parent_partref;
	124	u32 generation;
	125	u32 parent_block;
	126	u32 parent_generation;
	127	} udf;
9078dc08	128	__u32 raw[0];
6e91ea2b CH	129	};
6e91ea2b CH	130	};
a5694255 CH	131
	132	/**
	133	* struct export_operations - for nfsd to communicate with file systems
a5694255	134	* @encode_fh: encode a file handle fragment from a dentry
9b89ca7a MD	135	* @fh_to_dentry: find the implied object and get a dentry for it
9b89ca7a MD	136	* @fh_to_parent: find the implied object's parent and get a dentry for it
a5694255 CH	137	* @get_name: find the name for a given inode in a given directory
a5694255 CH	138	* @get_parent: find the parent of a given directory
f501912a	139	* @commit_metadata: commit metadata changes to stable storage
a5694255	140	*
dc7a0816	141	* See Documentation/filesystems/nfs/Exporting for details on how to use
e38f9817	142	* this interface correctly.
a5694255	143	*
a5694255 CH	144	* encode_fh:
	145	* @encode_fh should store in the file handle fragment @fh (using at most
	146	* @max_len bytes) information that can be used by @decode_fh to recover the
25985edc	147	* file referred to by the &struct dentry @de. If the @connectable flag is
a5694255 CH	148	* set, the encode_fh() should store sufficient information so that a good
	149	* attempt can be made to find not only the file but also it's place in the
	150	* filesystem. This typically means storing a reference to de->d_parent in
5fe0c237 AK	151	* the filehandle fragment. encode_fh() should return the fileid_type on
	152	* success and on error returns 255 (if the space needed to encode fh is
	153	* greater than @max_len*4 bytes). On error @max_len contains the minimum
	154	* size(in 4 byte unit) needed to encode the file handle.
a5694255	155	*
2596110a CH	156	* fh_to_dentry:
	157	* @fh_to_dentry is given a &struct super_block (@sb) and a file handle
	158	* fragment (@fh, @fh_len). It should return a &struct dentry which refers
	159	* to the same file that the file handle fragment refers to. If it cannot,
09bb8bff N	160	* it should return a %NULL pointer if the file cannot be found, or an
	161	* %ERR_PTR error code of %ENOMEM if a memory allocation failure occurred.
	162	* Any other error code is treated like %NULL, and will cause an %ESTALE error
	163	* for callers of exportfs_decode_fh().
	164	* Any suitable dentry can be returned including, if necessary, a new dentry
	165	* created with d_alloc_root. The caller can then find any other extant
	166	* dentries by following the d_alias links.
2596110a CH	167	*
	168	* fh_to_parent:
	169	* Same as @fh_to_dentry, except that it returns a pointer to the parent
	170	* dentry if it was encoded into the filehandle fragment by @encode_fh.
	171	*
a5694255 CH	172	* get_name:
	173	* @get_name should find a name for the given @child in the given @parent
	174	* directory. The name should be stored in the @name (with the
	175	* understanding that it is already pointing to a a %NAME_MAX+1 sized
	176	* buffer. get_name() should return %0 on success, a negative error code
	177	* or error. @get_name will be called without @parent->i_mutex held.
	178	*
	179	* get_parent:
	180	* @get_parent should find the parent directory for the given @child which
	181	* is also a directory. In the event that it cannot be found, or storage
	182	* space cannot be allocated, a %ERR_PTR should be returned.
	183	*
f501912a BM	184	* commit_metadata:
	185	* @commit_metadata should commit metadata changes to stable storage.
	186	*
a5694255 CH	187	* Locking rules:
	188	* get_parent is called with child->d_inode->i_mutex down
	189	* get_name is not (which is possibly inconsistent)
	190	*/
	191
	192	struct export_operations {
b0b0382b AV	193	int (encode_fh)(struct inode inode, __u32 fh, int max_len,
b0b0382b AV	194	struct inode *parent);
2596110a CH	195	struct dentry * (fh_to_dentry)(struct super_block sb, struct fid *fid,
	196	int fh_len, int fh_type);
	197	struct dentry * (fh_to_parent)(struct super_block sb, struct fid *fid,
	198	int fh_len, int fh_type);
a5694255 CH	199	int (get_name)(struct dentry parent, char *name,
	200	struct dentry *child);
	201	struct dentry * (get_parent)(struct dentry child);
f501912a	202	int (commit_metadata)(struct inode inode);
7fbc1067 CH	203
	204	int (get_uuid)(struct super_block sb, u8 buf, u32 len, u64 *offset);
	205	int (map_blocks)(struct inode inode, loff_t offset,
	206	u64 len, struct iomap *iomap,
	207	bool write, u32 *device_generation);
	208	int (commit_blocks)(struct inode inode, struct iomap *iomaps,
	209	int nr_iomaps, struct iattr *iattr);
a5694255 CH	210	};
a5694255 CH	211
711c7bf9 CG	212	extern int exportfs_encode_inode_fh(struct inode inode, struct fid fid,
711c7bf9 CG	213	int max_len, struct inode parent);
6e91ea2b CH	214	extern int exportfs_encode_fh(struct dentry dentry, struct fid fid,
	215	int *max_len, int connectable);
	216	extern struct dentry exportfs_decode_fh(struct vfsmount mnt, struct fid *fid,
d37065cd CH	217	int fh_len, int fileid_type, int (acceptable)(void , struct dentry *),
	218	void *context);
	219
2596110a CH	220	/*
	221	* Generic helpers for filesystems.
	222	*/
	223	extern struct dentry generic_fh_to_dentry(struct super_block sb,
	224	struct fid *fid, int fh_len, int fh_type,
	225	struct inode (get_inode) (struct super_block *sb, u64 ino, u32 gen));
	226	extern struct dentry generic_fh_to_parent(struct super_block sb,
	227	struct fid *fid, int fh_len, int fh_type,
	228	struct inode (get_inode) (struct super_block *sb, u64 ino, u32 gen));
	229
a5694255	230	#endif /* LINUX_EXPORTFS_H */