On 2019/4/16 上午12:50, David Sterba wrote:
> On Sat, Apr 13, 2019 at 07:48:51AM +0800, Qu Wenruo wrote:
>>
>>
>> On 2019/4/12 下午11:46, David Sterba wrote:
>>> On Thu, Apr 04, 2019 at 02:45:29PM +0800, Qu Wenruo wrote:
>>>> +struct btrfs_ref {
>>>> +	enum btrfs_ref_type type;
>>>> +	int action;
>>>> +
>>>> +	/*
>>>> +	 * Only use parent pointers as backref (SHARED_BLOCK_REF or
>>>> +	 * SHARED_DATA_REF) for this extent and its children.
>>>> +	 * Set for reloc trees.
>>>> +	 */
>>>> +	bool only_backreferences:1;
>>>
>>> I renamed this to only_backrefs and was surprised that there were no
>>> compilation errors, ie. this member is not used at all ...
>>
>> Yep, for callers who really uses this member, they just set @parent, and
>> that's all.
> 
> So there's nothing in the old and new code that uses it, then why do you
> add it? If this is for some existing patchset then ok, keep it there but
> otherwise remove it.

It should be removed.
My bad, at the time of writing, I didn't get the point that @parent is
enough to info to use SHARED_BLOCK_REF_KEY.

Would you mind to fold this removal?

Thanks,
Qu