void set_pnfs_layoutdriver(struct nfs_server *, u32 id);
void unset_pnfs_layoutdriver(struct nfs_server *);
enum pnfs_try_status pnfs_try_to_write_data(struct nfs_write_data *,
void set_pnfs_layoutdriver(struct nfs_server *, u32 id);
void unset_pnfs_layoutdriver(struct nfs_server *);
enum pnfs_try_status pnfs_try_to_write_data(struct nfs_write_data *,