From 2596110a3994593f6aa3e2bb76345ad4791b1a14 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Sun, 21 Oct 2007 16:42:05 -0700 Subject: exportfs: add new methods Add the guts for the new filesystem API to exportfs. There's now a fh_to_dentry method that returns a dentry for the object looked for given a filehandle fragment, and a fh_to_parent operation that returns the dentry for the encoded parent directory in case the file handle contains it. There are default implementations for these methods that only take a callback for an nfs-enhanced iget variant and implement the rest of the semantics. Signed-off-by: Christoph Hellwig Cc: Neil Brown Cc: "J. Bruce Fields" Cc: Cc: Dave Kleikamp Cc: Anton Altaparmakov Cc: David Chinner Cc: Timothy Shimmin Cc: OGAWA Hirofumi Cc: Hugh Dickins Cc: Chris Mason Cc: Jeff Mahoney Cc: "Vladimir V. Saveliev" Cc: Steven Whitehouse Cc: Mark Fasheh Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/exportfs.h | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) (limited to 'include/linux/exportfs.h') diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h index 06178a1336f..b44f6b6871c 100644 --- a/include/linux/exportfs.h +++ b/include/linux/exportfs.h @@ -4,6 +4,7 @@ #include struct dentry; +struct inode; struct super_block; struct vfsmount; @@ -101,6 +102,21 @@ struct fid { * 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 @@ -139,6 +155,10 @@ struct export_operations { void *context); 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); @@ -161,4 +181,14 @@ 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 */ -- cgit v1.2.3