#ifndef LINUX_EXPORTFS_H

#define LINUX_EXPORTFS_H 1

#include <linux/types.h>

struct dentry;

struct inode;

struct super_block;

struct vfsmount;

/*

 * 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,

};

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

 *

 * See Documentation/filesystems/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 refered 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 number of bytes

 *    stored or a negative error code such as %-ENOSPC

 *

 * 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 was found but no acceptable

 *    &dentries were available, or an %ERR_PTR error code indicating why it

 *    couldn't be found (e.g. %ENOENT or %ENOMEM).  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.

 *

 * 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 dentry *de, __u32 *fh, int *max_len,

			int connectable);

	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);

};

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 */