ecryptfs_lower_path
path = ecryptfs_lower_path(ecryptfs_dentry);
struct path path = ecryptfs_lower_path(file->f_path.dentry);
struct path path = ecryptfs_lower_path(in->f_path.dentry);
struct path lower_path = ecryptfs_lower_path(dentry);
struct path path = ecryptfs_lower_path(dentry);