#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,
};
struct fid {
union {
struct {
u32 ino;
u32 gen;
u32 parent_ino;
u32 parent_gen;
} i32;
__u32 raw[6];
};
};
/**
* struct export_operations - for nfsd to communicate with file systems
* @decode_fh: decode a file handle fragment and return a &struct dentry
* @encode_fh: encode a file handle fragment from a dentry
* @get_name: find the name for a given inode in a given directory
* @get_parent: find the parent of a given directory
* @get_dentry: find a dentry for the inode given a file handle sub-fragment
*
* 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 */
