kernel-ark/include/linux/exportfs.h
Ben Myers f501912a35 commit_metadata export operation replacing nfsd_sync_dir
- Add commit_metadata export_operation to allow the underlying filesystem to
decide how to commit an inode most efficiently.

- Usage of nfsd_sync_dir and write_inode_now has been replaced with the
commit_metadata function that takes a svc_fh.

- The commit_metadata function calls the commit_metadata export_op if it's
there, or else falls back to sync_inode instead of fsync and write_inode_now
because only metadata need be synced here.

- nfsd4_sync_rec_dir now uses vfs_fsync so that commit_metadata can be static

Signed-off-by: Ben Myers <bpm@sgi.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-02-20 13:13:44 -08:00

179 lines
5.9 KiB
C

#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,
/*
* 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,
};
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 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.
*
* 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 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);
int (*commit_metadata)(struct inode *inode);
};
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 */