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Diffstat (limited to 'include/linux/exportfs.h')
| -rw-r--r-- | include/linux/exportfs.h | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h new file mode 100644 index 000000000..fe848901f --- /dev/null +++ b/include/linux/exportfs.h @@ -0,0 +1,250 @@ +/* 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; + __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.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); + u64 (*fetch_iversion)(struct inode *); +#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 + */ + 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 */ |