Re: [PATCH] erofs: fix compacted_2b if compacted_4b_initial > totalidx

Chao Yu
2021-09-23T15:13:34Z

On 2021/9/23 19:49, Gao Xiang wrote:
> On Tue, Sep 14, 2021 at 12:57:48PM +0800, Yue Hu wrote:
>> On Tue, 14 Sep 2021 12:37:14 +0800
>> Gao Xiang <hsiangkao@linux.alibaba.com> wrote:
>>
>>> On Tue, Sep 14, 2021 at 11:59:15AM +0800, Yue Hu wrote:
>>>> From: Yue Hu <huyue2@yulong.com>
>>>>
>>>> Currently, the whole indexes will only be compacted 4B if
>>>> compacted_4b_initial > totalidx. So, the calculated compacted_2b
>>>> is worthless for that case. It may waste CPU resources.
>>>>
>>>> No need to update compacted_4b_initial as mkfs since it's used to
>>>> fulfill the alignment of the 1st compacted_2b pack and would handle
>>>> the case above.
>>>>
>>>> We also need to clarify compacted_4b_end here. It's used for the
>>>> last lclusters which aren't fitted in the previous compacted_2b
>>>> packs.
>>>>
>>>> Some messages are from Xiang.
>>>>
>>>> Signed-off-by: Yue Hu <huyue2@yulong.com>
>>>
>>> Looks good to me,
>>> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
>>>
>>> (although I think the subject title would be better changed into
>>> "clear compacted_2b if compacted_4b_initial > totalidx"
>>
>> Yeah, 'clear' is much better for this change.
>>
>> Thanks.
>>
>>> since 'fix'-likewise words could trigger some AI bot for stable
>>> kernel backporting..)
>>>
>>> Thanks,
>>> Gao Xiang
>>>
>>>> ---
>>>> fs/erofs/zmap.c | 3 ++-
>>>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
>>>> index 9fb98d8..aeed404 100644
>>>> --- a/fs/erofs/zmap.c
>>>> +++ b/fs/erofs/zmap.c
>>>> @@ -369,7 +369,8 @@ static int compacted_load_cluster_from_disk(struct z_erofs_maprecorder *m,
>>>> if (compacted_4b_initial == 32 / 4)
>>>> compacted_4b_initial = 0;
>>>>
>>>> - if (vi->z_advise & Z_EROFS_ADVISE_COMPACTED_2B)
>>>> + if ((vi->z_advise & Z_EROFS_ADVISE_COMPACTED_2B) &&
>>>> + compacted_4b_initial <= totalidx) {
>
> btw, I've fixed up the build error due to redundant brace '{' when
> applying...

It looks good to me after above fix.

Reviewed-by: Chao Yu <chao@kernel.org>

Thanks,