[GitHub/mt8127/android_kernel_alcatel_ttab.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;

/*
 * 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,

	/*
	 * 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 */
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
6e91ea2b CH	11	/*
	12	* The fileid_type identifies how the file within the filesystem is encoded.
	13	* In theory this is freely set and parsed by the filesystem, but we try to
	14	* stick to conventions so we can share some generic code and don't confuse
	15	* sniffers like ethereal/wireshark.
	16	*
	17	* The filesystem must not use the value '0' or '0xff'.
	18	*/
	19	enum fid_type {
	20	/*
	21	* The root, or export point, of the filesystem.
	22	* (Never actually passed down to the filesystem.
	23	*/
	24	FILEID_ROOT = 0,
	25
	26	/*
	27	* 32bit inode number, 32 bit generation number.
	28	*/
	29	FILEID_INO32_GEN = 1,
	30
	31	/*
	32	* 32bit inode number, 32 bit generation number,
	33	* 32 bit parent directory inode number.
	34	*/
	35	FILEID_INO32_GEN_PARENT = 2,
221e583a RR	36
	37	/*
	38	* 32 bit block number, 16 bit partition reference,
	39	* 16 bit unused, 32 bit generation number.
	40	*/
	41	FILEID_UDF_WITHOUT_PARENT = 0x51,
	42
	43	/*
	44	* 32 bit block number, 16 bit partition reference,
	45	* 16 bit unused, 32 bit generation number,
	46	* 32 bit parent block number, 32 bit parent generation number
	47	*/
	48	FILEID_UDF_WITH_PARENT = 0x52,
6e91ea2b CH	49	};
	50
	51	struct fid {
	52	union {
	53	struct {
	54	u32 ino;
	55	u32 gen;
	56	u32 parent_ino;
	57	u32 parent_gen;
	58	} i32;
221e583a RR	59	struct {
	60	u32 block;
	61	u16 partref;
	62	u16 parent_partref;
	63	u32 generation;
	64	u32 parent_block;
	65	u32 parent_generation;
	66	} udf;
9078dc08	67	__u32 raw[0];
6e91ea2b CH	68	};
6e91ea2b CH	69	};
a5694255 CH	70
	71	/**
	72	* struct export_operations - for nfsd to communicate with file systems
a5694255	73	* @encode_fh: encode a file handle fragment from a dentry
9b89ca7a MD	74	* @fh_to_dentry: find the implied object and get a dentry for it
9b89ca7a MD	75	* @fh_to_parent: find the implied object's parent and get a dentry for it
a5694255 CH	76	* @get_name: find the name for a given inode in a given directory
a5694255 CH	77	* @get_parent: find the parent of a given directory
a5694255	78	*
e38f9817 CH	79	* See Documentation/filesystems/Exporting for details on how to use
e38f9817 CH	80	* this interface correctly.
a5694255	81	*
a5694255 CH	82	* encode_fh:
	83	* @encode_fh should store in the file handle fragment @fh (using at most
	84	* @max_len bytes) information that can be used by @decode_fh to recover the
	85	* file refered to by the &struct dentry @de. If the @connectable flag is
	86	* set, the encode_fh() should store sufficient information so that a good
	87	* attempt can be made to find not only the file but also it's place in the
	88	* filesystem. This typically means storing a reference to de->d_parent in
	89	* the filehandle fragment. encode_fh() should return the number of bytes
	90	* stored or a negative error code such as %-ENOSPC
	91	*
2596110a CH	92	* fh_to_dentry:
	93	* @fh_to_dentry is given a &struct super_block (@sb) and a file handle
	94	* fragment (@fh, @fh_len). It should return a &struct dentry which refers
	95	* to the same file that the file handle fragment refers to. If it cannot,
	96	* it should return a %NULL pointer if the file was found but no acceptable
	97	* &dentries were available, or an %ERR_PTR error code indicating why it
	98	* couldn't be found (e.g. %ENOENT or %ENOMEM). Any suitable dentry can be
	99	* returned including, if necessary, a new dentry created with d_alloc_root.
	100	* The caller can then find any other extant dentries by following the
	101	* d_alias links.
	102	*
	103	* fh_to_parent:
	104	* Same as @fh_to_dentry, except that it returns a pointer to the parent
	105	* dentry if it was encoded into the filehandle fragment by @encode_fh.
	106	*
a5694255 CH	107	* get_name:
	108	* @get_name should find a name for the given @child in the given @parent
	109	* directory. The name should be stored in the @name (with the
	110	* understanding that it is already pointing to a a %NAME_MAX+1 sized
	111	* buffer. get_name() should return %0 on success, a negative error code
	112	* or error. @get_name will be called without @parent->i_mutex held.
	113	*
	114	* get_parent:
	115	* @get_parent should find the parent directory for the given @child which
	116	* is also a directory. In the event that it cannot be found, or storage
	117	* space cannot be allocated, a %ERR_PTR should be returned.
	118	*
a5694255 CH	119	* Locking rules:
	120	* get_parent is called with child->d_inode->i_mutex down
	121	* get_name is not (which is possibly inconsistent)
	122	*/
	123
	124	struct export_operations {
a5694255 CH	125	int (encode_fh)(struct dentry de, __u32 fh, int max_len,
a5694255 CH	126	int connectable);
2596110a CH	127	struct dentry * (fh_to_dentry)(struct super_block sb, struct fid *fid,
	128	int fh_len, int fh_type);
	129	struct dentry * (fh_to_parent)(struct super_block sb, struct fid *fid,
	130	int fh_len, int fh_type);
a5694255 CH	131	int (get_name)(struct dentry parent, char *name,
	132	struct dentry *child);
	133	struct dentry * (get_parent)(struct dentry child);
a5694255 CH	134	};
a5694255 CH	135
6e91ea2b CH	136	extern int exportfs_encode_fh(struct dentry dentry, struct fid fid,
	137	int *max_len, int connectable);
	138	extern struct dentry exportfs_decode_fh(struct vfsmount mnt, struct fid *fid,
d37065cd CH	139	int fh_len, int fileid_type, int (acceptable)(void , struct dentry *),
	140	void *context);
	141
2596110a CH	142	/*
	143	* Generic helpers for filesystems.
	144	*/
	145	extern struct dentry generic_fh_to_dentry(struct super_block sb,
	146	struct fid *fid, int fh_len, int fh_type,
	147	struct inode (get_inode) (struct super_block *sb, u64 ino, u32 gen));
	148	extern struct dentry generic_fh_to_parent(struct super_block sb,
	149	struct fid *fid, int fh_len, int fh_type,
	150	struct inode (get_inode) (struct super_block *sb, u64 ino, u32 gen));
	151
a5694255	152	#endif /* LINUX_EXPORTFS_H */