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     ˆËÊƒ}ÖÃÉ¿Ç &    /* SPDX-License-Identifier: GPL-2.0 */
#ifndef LINUX_EXPORTFS_H
#define LINUX_EXPORTFS_H 1

#include <linux/types.h>
#include <linux/path.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,

	/*
	 * 64 bit unique kernfs id
	 */
	FILEID_KERNFS = 0xfe,

	/*
	 * 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];
	};
};

enum handle_to_path_flags {
	HANDLE_CHECK_PERMS   = (1 << 0),
	HANDLE_CHECK_SUBTREE = (1 << 1),
};

struct handle_to_path_ctx {
	struct path root;
	enum handle_to_path_flags flags;
	unsigned int fh_flags;
};

#define EXPORT_FH_CONNECTABLE	0x1 /* Encode file handle with parent */
#define EXPORT_FH_FID		0x2 /* File handle may be non-decodeable */
#define EXPORT_FH_DIR_ONLY	0x4 /* Only decode file handle for a directory */

/**
 * 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.rst 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) in