simple_offset_add
int simple_offset_add(struct offset_ctx *octx, struct dentry *dentry);
error = simple_offset_add(shmem_get_offset_ctx(dir), dentry);
ret = simple_offset_add(shmem_get_offset_ctx(dir), dentry);
error = simple_offset_add(shmem_get_offset_ctx(new_dir), new_dentry);
error = simple_offset_add(shmem_get_offset_ctx(dir), dentry);