[mirror_ubuntu-bionic-kernel.git] / include / linux / exportfs.h

#ifndef LINUX_EXPORTFS_H
#define LINUX_EXPORTFS_H 1

#include <linux/types.h>

struct dentry;
struct inode;
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,

	/*
	 * 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 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.
 *
 * 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);
};

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;
2596110a	7	struct inode;
a5694255	8	struct super_block;
d37065cd	9	struct vfsmount;
a5694255	10
990d6c2d AK	11	/* limit the handle size to NFSv4 handle size now */
	12	#define MAX_HANDLE_SZ 128
	13
6e91ea2b CH	14	/*
	15	* The fileid_type identifies how the file within the filesystem is encoded.
	16	* In theory this is freely set and parsed by the filesystem, but we try to
	17	* stick to conventions so we can share some generic code and don't confuse
	18	* sniffers like ethereal/wireshark.
	19	*
	20	* The filesystem must not use the value '0' or '0xff'.
	21	*/
	22	enum fid_type {
	23	/*
	24	* The root, or export point, of the filesystem.
	25	* (Never actually passed down to the filesystem.
	26	*/
	27	FILEID_ROOT = 0,
	28
	29	/*
	30	* 32bit inode number, 32 bit generation number.
	31	*/
	32	FILEID_INO32_GEN = 1,
	33
	34	/*
	35	* 32bit inode number, 32 bit generation number,
	36	* 32 bit parent directory inode number.
	37	*/
	38	FILEID_INO32_GEN_PARENT = 2,
221e583a	39
e4464fac DW	40	/*
	41	* 64 bit object ID, 64 bit root object ID,
	42	* 32 bit generation number.
	43	*/
	44	FILEID_BTRFS_WITHOUT_PARENT = 0x4d,
	45
	46	/*
	47	* 64 bit object ID, 64 bit root object ID,
	48	* 32 bit generation number,
	49	* 64 bit parent object ID, 32 bit parent generation.
	50	*/
	51	FILEID_BTRFS_WITH_PARENT = 0x4e,
	52
	53	/*
	54	* 64 bit object ID, 64 bit root object ID,
	55	* 32 bit generation number,
	56	* 64 bit parent object ID, 32 bit parent generation,
	57	* 64 bit parent root object ID.
	58	*/
	59	FILEID_BTRFS_WITH_PARENT_ROOT = 0x4f,
	60
221e583a RR	61	/*
	62	* 32 bit block number, 16 bit partition reference,
	63	* 16 bit unused, 32 bit generation number.
	64	*/
	65	FILEID_UDF_WITHOUT_PARENT = 0x51,
	66
	67	/*
	68	* 32 bit block number, 16 bit partition reference,
	69	* 16 bit unused, 32 bit generation number,
	70	* 32 bit parent block number, 32 bit parent generation number
	71	*/
	72	FILEID_UDF_WITH_PARENT = 0x52,
8e656fd5 RK	73
	74	/*
	75	* 64 bit checkpoint number, 64 bit inode number,
	76	* 32 bit generation number.
	77	*/
	78	FILEID_NILFS_WITHOUT_PARENT = 0x61,
	79
	80	/*
	81	* 64 bit checkpoint number, 64 bit inode number,
	82	* 32 bit generation number, 32 bit parent generation.
	83	* 64 bit parent inode number.
	84	*/
	85	FILEID_NILFS_WITH_PARENT = 0x62,
216b6cbd NJ	86
	87	/*
	88	* Filesystems must not use 0xff file ID.
	89	*/
	90	FILEID_INVALID = 0xff,
6e91ea2b CH	91	};
	92
	93	struct fid {
	94	union {
	95	struct {
	96	u32 ino;
	97	u32 gen;
	98	u32 parent_ino;
	99	u32 parent_gen;
	100	} i32;
221e583a RR	101	struct {
	102	u32 block;
	103	u16 partref;
	104	u16 parent_partref;
	105	u32 generation;
	106	u32 parent_block;
	107	u32 parent_generation;
	108	} udf;
9078dc08	109	__u32 raw[0];
6e91ea2b CH	110	};
6e91ea2b CH	111	};
a5694255 CH	112
	113	/**
	114	* struct export_operations - for nfsd to communicate with file systems
a5694255	115	* @encode_fh: encode a file handle fragment from a dentry
9b89ca7a MD	116	* @fh_to_dentry: find the implied object and get a dentry for it
9b89ca7a MD	117	* @fh_to_parent: find the implied object's parent and get a dentry for it
a5694255 CH	118	* @get_name: find the name for a given inode in a given directory
a5694255 CH	119	* @get_parent: find the parent of a given directory
f501912a	120	* @commit_metadata: commit metadata changes to stable storage
a5694255	121	*
dc7a0816	122	* See Documentation/filesystems/nfs/Exporting for details on how to use
e38f9817	123	* this interface correctly.
a5694255	124	*
a5694255 CH	125	* encode_fh:
	126	* @encode_fh should store in the file handle fragment @fh (using at most
	127	* @max_len bytes) information that can be used by @decode_fh to recover the
25985edc	128	* file referred to by the &struct dentry @de. If the @connectable flag is
a5694255 CH	129	* set, the encode_fh() should store sufficient information so that a good
	130	* attempt can be made to find not only the file but also it's place in the
	131	* filesystem. This typically means storing a reference to de->d_parent in
5fe0c237 AK	132	* the filehandle fragment. encode_fh() should return the fileid_type on
	133	* success and on error returns 255 (if the space needed to encode fh is
	134	* greater than @max_len*4 bytes). On error @max_len contains the minimum
	135	* size(in 4 byte unit) needed to encode the file handle.
a5694255	136	*
2596110a CH	137	* fh_to_dentry:
	138	* @fh_to_dentry is given a &struct super_block (@sb) and a file handle
	139	* fragment (@fh, @fh_len). It should return a &struct dentry which refers
	140	* to the same file that the file handle fragment refers to. If it cannot,
	141	* it should return a %NULL pointer if the file was found but no acceptable
	142	* &dentries were available, or an %ERR_PTR error code indicating why it
	143	* couldn't be found (e.g. %ENOENT or %ENOMEM). Any suitable dentry can be
	144	* returned including, if necessary, a new dentry created with d_alloc_root.
	145	* The caller can then find any other extant dentries by following the
	146	* d_alias links.
	147	*
	148	* fh_to_parent:
	149	* Same as @fh_to_dentry, except that it returns a pointer to the parent
	150	* dentry if it was encoded into the filehandle fragment by @encode_fh.
	151	*
a5694255 CH	152	* get_name:
	153	* @get_name should find a name for the given @child in the given @parent
	154	* directory. The name should be stored in the @name (with the
	155	* understanding that it is already pointing to a a %NAME_MAX+1 sized
	156	* buffer. get_name() should return %0 on success, a negative error code
	157	* or error. @get_name will be called without @parent->i_mutex held.
	158	*
	159	* get_parent:
	160	* @get_parent should find the parent directory for the given @child which
	161	* is also a directory. In the event that it cannot be found, or storage
	162	* space cannot be allocated, a %ERR_PTR should be returned.
	163	*
f501912a BM	164	* commit_metadata:
	165	* @commit_metadata should commit metadata changes to stable storage.
	166	*
a5694255 CH	167	* Locking rules:
	168	* get_parent is called with child->d_inode->i_mutex down
	169	* get_name is not (which is possibly inconsistent)
	170	*/
	171
	172	struct export_operations {
b0b0382b AV	173	int (encode_fh)(struct inode inode, __u32 fh, int max_len,
b0b0382b AV	174	struct inode *parent);
2596110a CH	175	struct dentry * (fh_to_dentry)(struct super_block sb, struct fid *fid,
	176	int fh_len, int fh_type);
	177	struct dentry * (fh_to_parent)(struct super_block sb, struct fid *fid,
	178	int fh_len, int fh_type);
a5694255 CH	179	int (get_name)(struct dentry parent, char *name,
	180	struct dentry *child);
	181	struct dentry * (get_parent)(struct dentry child);
f501912a	182	int (commit_metadata)(struct inode inode);
a5694255 CH	183	};
a5694255 CH	184
711c7bf9 CG	185	extern int exportfs_encode_inode_fh(struct inode inode, struct fid fid,
711c7bf9 CG	186	int max_len, struct inode parent);
6e91ea2b CH	187	extern int exportfs_encode_fh(struct dentry dentry, struct fid fid,
	188	int *max_len, int connectable);
	189	extern struct dentry exportfs_decode_fh(struct vfsmount mnt, struct fid *fid,
d37065cd CH	190	int fh_len, int fileid_type, int (acceptable)(void , struct dentry *),
	191	void *context);
	192
2596110a CH	193	/*
	194	* Generic helpers for filesystems.
	195	*/
	196	extern struct dentry generic_fh_to_dentry(struct super_block sb,
	197	struct fid *fid, int fh_len, int fh_type,
	198	struct inode (get_inode) (struct super_block *sb, u64 ino, u32 gen));
	199	extern struct dentry generic_fh_to_parent(struct super_block sb,
	200	struct fid *fid, int fh_len, int fh_type,
	201	struct inode (get_inode) (struct super_block *sb, u64 ino, u32 gen));
	202
a5694255	203	#endif /* LINUX_EXPORTFS_H */