[linux-block.git] / include / linux / exportfs.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef LINUX_EXPORTFS_H
#define LINUX_EXPORTFS_H 1

#include <linux/types.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;
		DECLARE_FLEX_ARRAY(__u32, raw);
	};
};

/**
 * 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) 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 cannot be found, or an
 *    %ERR_PTR error code of %ENOMEM if a memory allocation failure occurred.
 *    Any other error code is treated like %NULL, and will cause an %ESTALE error
 *    for callers of exportfs_decode_fh().
 *    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 %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);

	int (*get_uuid)(struct super_block *sb, u8 *buf, u32 *len, u64 *offset);
	int (*map_blocks)(struct inode *inode, loff_t offset,
			  u64 len, struct iomap *iomap,
			  bool write, u32 *device_generation);
	int (*commit_blocks)(struct inode *inode, struct iomap *iomaps,
			     int nr_iomaps, struct iattr *iattr);
#define	EXPORT_OP_NOWCC			(0x1) /* don't collect v3 wcc data */
#define	EXPORT_OP_NOSUBTREECHK		(0x2) /* no subtree checking */
#define	EXPORT_OP_CLOSE_BEFORE_UNLINK	(0x4) /* close files before unlink */
#define EXPORT_OP_REMOTE_FS		(0x8) /* Filesystem is remote */
#define EXPORT_OP_NOATOMIC_ATTR		(0x10) /* Filesystem cannot supply
						  atomic attribute updates
						*/
#define EXPORT_OP_FLUSH_ON_CLOSE	(0x20) /* fs flushes file data on close */
	unsigned long	flags;
};

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_raw(struct vfsmount *mnt,
					     struct fid *fid, int fh_len,
					     int fileid_type,
					     int (*acceptable)(void *, struct dentry *),
					     void *context);
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
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
a5694255 CH	2	#ifndef LINUX_EXPORTFS_H
	3	#define LINUX_EXPORTFS_H 1
	4
	5	#include <linux/types.h>
	6
	7	struct dentry;
7fbc1067	8	struct iattr;
2596110a	9	struct inode;
199a31c6	10	struct iomap;
a5694255	11	struct super_block;
d37065cd	12	struct vfsmount;
a5694255	13
990d6c2d AK	14	/* limit the handle size to NFSv4 handle size now */
	15	#define MAX_HANDLE_SZ 128
	16
6e91ea2b CH	17	/*
	18	* The fileid_type identifies how the file within the filesystem is encoded.
	19	* In theory this is freely set and parsed by the filesystem, but we try to
	20	* stick to conventions so we can share some generic code and don't confuse
	21	* sniffers like ethereal/wireshark.
	22	*
	23	* The filesystem must not use the value '0' or '0xff'.
	24	*/
	25	enum fid_type {
	26	/*
	27	* The root, or export point, of the filesystem.
	28	* (Never actually passed down to the filesystem.
	29	*/
	30	FILEID_ROOT = 0,
	31
	32	/*
	33	* 32bit inode number, 32 bit generation number.
	34	*/
	35	FILEID_INO32_GEN = 1,
	36
	37	/*
	38	* 32bit inode number, 32 bit generation number,
	39	* 32 bit parent directory inode number.
	40	*/
	41	FILEID_INO32_GEN_PARENT = 2,
221e583a	42
e4464fac DW	43	/*
	44	* 64 bit object ID, 64 bit root object ID,
	45	* 32 bit generation number.
	46	*/
	47	FILEID_BTRFS_WITHOUT_PARENT = 0x4d,
	48
	49	/*
	50	* 64 bit object ID, 64 bit root object ID,
	51	* 32 bit generation number,
	52	* 64 bit parent object ID, 32 bit parent generation.
	53	*/
	54	FILEID_BTRFS_WITH_PARENT = 0x4e,
	55
	56	/*
	57	* 64 bit object ID, 64 bit root object ID,
	58	* 32 bit generation number,
	59	* 64 bit parent object ID, 32 bit parent generation,
	60	* 64 bit parent root object ID.
	61	*/
	62	FILEID_BTRFS_WITH_PARENT_ROOT = 0x4f,
	63
221e583a RR	64	/*
	65	* 32 bit block number, 16 bit partition reference,
	66	* 16 bit unused, 32 bit generation number.
	67	*/
	68	FILEID_UDF_WITHOUT_PARENT = 0x51,
	69
	70	/*
	71	* 32 bit block number, 16 bit partition reference,
	72	* 16 bit unused, 32 bit generation number,
	73	* 32 bit parent block number, 32 bit parent generation number
	74	*/
	75	FILEID_UDF_WITH_PARENT = 0x52,
8e656fd5 RK	76
	77	/*
	78	* 64 bit checkpoint number, 64 bit inode number,
	79	* 32 bit generation number.
	80	*/
	81	FILEID_NILFS_WITHOUT_PARENT = 0x61,
	82
	83	/*
	84	* 64 bit checkpoint number, 64 bit inode number,
	85	* 32 bit generation number, 32 bit parent generation.
	86	* 64 bit parent inode number.
	87	*/
	88	FILEID_NILFS_WITH_PARENT = 0x62,
216b6cbd	89
ea3983ac NJ	90	/*
	91	* 32 bit generation number, 40 bit i_pos.
	92	*/
	93	FILEID_FAT_WITHOUT_PARENT = 0x71,
	94
	95	/*
	96	* 32 bit generation number, 40 bit i_pos,
	97	* 32 bit parent generation number, 40 bit parent i_pos
	98	*/
	99	FILEID_FAT_WITH_PARENT = 0x72,
	100
cb776592 DE	101	/*
	102	* 128 bit child FID (struct lu_fid)
	103	* 128 bit parent FID (struct lu_fid)
	104	*/
	105	FILEID_LUSTRE = 0x97,
	106
33c5ac91 TH	107	/*
	108	* 64 bit unique kernfs id
	109	*/
	110	FILEID_KERNFS = 0xfe,
	111
216b6cbd NJ	112	/*
	113	* Filesystems must not use 0xff file ID.
	114	*/
	115	FILEID_INVALID = 0xff,
6e91ea2b CH	116	};
	117
	118	struct fid {
	119	union {
	120	struct {
	121	u32 ino;
	122	u32 gen;
	123	u32 parent_ino;
	124	u32 parent_gen;
	125	} i32;
221e583a RR	126	struct {
	127	u32 block;
	128	u16 partref;
	129	u16 parent_partref;
	130	u32 generation;
	131	u32 parent_block;
	132	u32 parent_generation;
	133	} udf;
37e2b570	134	DECLARE_FLEX_ARRAY(__u32, raw);
6e91ea2b CH	135	};
6e91ea2b CH	136	};
a5694255 CH	137
	138	/**
	139	* struct export_operations - for nfsd to communicate with file systems
a5694255	140	* @encode_fh: encode a file handle fragment from a dentry
9b89ca7a MD	141	* @fh_to_dentry: find the implied object and get a dentry for it
9b89ca7a MD	142	* @fh_to_parent: find the implied object's parent and get a dentry for it
a5694255 CH	143	* @get_name: find the name for a given inode in a given directory
a5694255 CH	144	* @get_parent: find the parent of a given directory
f501912a	145	* @commit_metadata: commit metadata changes to stable storage
a5694255	146	*
ec23eb54	147	* See Documentation/filesystems/nfs/exporting.rst for details on how to use
e38f9817	148	* this interface correctly.
a5694255	149	*
a5694255 CH	150	* encode_fh:
	151	* @encode_fh should store in the file handle fragment @fh (using at most
	152	* @max_len bytes) information that can be used by @decode_fh to recover the
25985edc	153	* file referred to by the &struct dentry @de. If the @connectable flag is
a5694255 CH	154	* set, the encode_fh() should store sufficient information so that a good
	155	* attempt can be made to find not only the file but also it's place in the
	156	* filesystem. This typically means storing a reference to de->d_parent in
5fe0c237 AK	157	* the filehandle fragment. encode_fh() should return the fileid_type on
	158	* success and on error returns 255 (if the space needed to encode fh is
	159	* greater than @max_len*4 bytes). On error @max_len contains the minimum
	160	* size(in 4 byte unit) needed to encode the file handle.
a5694255	161	*
2596110a CH	162	* fh_to_dentry:
	163	* @fh_to_dentry is given a &struct super_block (@sb) and a file handle
	164	* fragment (@fh, @fh_len). It should return a &struct dentry which refers
	165	* to the same file that the file handle fragment refers to. If it cannot,
09bb8bff N	166	* it should return a %NULL pointer if the file cannot be found, or an
	167	* %ERR_PTR error code of %ENOMEM if a memory allocation failure occurred.
	168	* Any other error code is treated like %NULL, and will cause an %ESTALE error
	169	* for callers of exportfs_decode_fh().
	170	* Any suitable dentry can be returned including, if necessary, a new dentry
	171	* created with d_alloc_root. The caller can then find any other extant
	172	* dentries by following the d_alias links.
2596110a CH	173	*
	174	* fh_to_parent:
	175	* Same as @fh_to_dentry, except that it returns a pointer to the parent
	176	* dentry if it was encoded into the filehandle fragment by @encode_fh.
	177	*
a5694255 CH	178	* get_name:
	179	* @get_name should find a name for the given @child in the given @parent
	180	* directory. The name should be stored in the @name (with the
cd1a406f	181	* understanding that it is already pointing to a %NAME_MAX+1 sized
a5694255 CH	182	* buffer. get_name() should return %0 on success, a negative error code
	183	* or error. @get_name will be called without @parent->i_mutex held.
	184	*
	185	* get_parent:
	186	* @get_parent should find the parent directory for the given @child which
	187	* is also a directory. In the event that it cannot be found, or storage
	188	* space cannot be allocated, a %ERR_PTR should be returned.
	189	*
f501912a BM	190	* commit_metadata:
	191	* @commit_metadata should commit metadata changes to stable storage.
	192	*
a5694255 CH	193	* Locking rules:
	194	* get_parent is called with child->d_inode->i_mutex down
	195	* get_name is not (which is possibly inconsistent)
	196	*/
	197
	198	struct export_operations {
b0b0382b AV	199	int (encode_fh)(struct inode inode, __u32 fh, int max_len,
b0b0382b AV	200	struct inode *parent);
2596110a CH	201	struct dentry * (fh_to_dentry)(struct super_block sb, struct fid *fid,
	202	int fh_len, int fh_type);
	203	struct dentry * (fh_to_parent)(struct super_block sb, struct fid *fid,
	204	int fh_len, int fh_type);
a5694255 CH	205	int (get_name)(struct dentry parent, char *name,
	206	struct dentry *child);
	207	struct dentry * (get_parent)(struct dentry child);
f501912a	208	int (commit_metadata)(struct inode inode);
7fbc1067 CH	209
	210	int (get_uuid)(struct super_block sb, u8 buf, u32 len, u64 *offset);
	211	int (map_blocks)(struct inode inode, loff_t offset,
	212	u64 len, struct iomap *iomap,
	213	bool write, u32 *device_generation);
	214	int (commit_blocks)(struct inode inode, struct iomap *iomaps,
	215	int nr_iomaps, struct iattr *iattr);
7f84b488 JL	216	#define EXPORT_OP_NOWCC (0x1) /* don't collect v3 wcc data */
	217	#define EXPORT_OP_NOSUBTREECHK (0x2) /* no subtree checking */
	218	#define EXPORT_OP_CLOSE_BEFORE_UNLINK (0x4) /* close files before unlink */
01cbf385	219	#define EXPORT_OP_REMOTE_FS (0x8) /* Filesystem is remote */
716a8bc7 TM	220	#define EXPORT_OP_NOATOMIC_ATTR (0x10) /* Filesystem cannot supply
	221	atomic attribute updates
	222	*/
dcb779fc	223	#define EXPORT_OP_FLUSH_ON_CLOSE (0x20) /* fs flushes file data on close */
daab110e	224	unsigned long flags;
a5694255 CH	225	};
a5694255 CH	226
711c7bf9 CG	227	extern int exportfs_encode_inode_fh(struct inode inode, struct fid fid,
711c7bf9 CG	228	int max_len, struct inode parent);
6e91ea2b CH	229	extern int exportfs_encode_fh(struct dentry dentry, struct fid fid,
6e91ea2b CH	230	int *max_len, int connectable);
d045465f TM	231	extern struct dentry exportfs_decode_fh_raw(struct vfsmount mnt,
	232	struct fid *fid, int fh_len,
	233	int fileid_type,
	234	int (acceptable)(void , struct dentry *),
	235	void *context);
6e91ea2b	236	extern struct dentry exportfs_decode_fh(struct vfsmount mnt, struct fid *fid,
d37065cd CH	237	int fh_len, int fileid_type, int (acceptable)(void , struct dentry *),
	238	void *context);
	239
2596110a CH	240	/*
	241	* Generic helpers for filesystems.
	242	*/
	243	extern struct dentry generic_fh_to_dentry(struct super_block sb,
	244	struct fid *fid, int fh_len, int fh_type,
	245	struct inode (get_inode) (struct super_block *sb, u64 ino, u32 gen));
	246	extern struct dentry generic_fh_to_parent(struct super_block sb,
	247	struct fid *fid, int fh_len, int fh_type,
	248	struct inode (get_inode) (struct super_block *sb, u64 ino, u32 gen));
	249
a5694255	250	#endif /* LINUX_EXPORTFS_H */