Re: [PATCH v2] btrfs-progs: calculate disk space that a subvol could free

[Wang Shilong <wangsl.fnst@cn.fujitsu.com>]

On 10/07/2013 10:47 AM, Anand Jain wrote:
>
>
>> If we want to speed up this progress, i think we can split it into two parts:
>>
>> 1. First to search inline extent_data
>> 2. Secondly search in extent tree to calculate (extent refs=1)
>>
>> This will avoid n*n rather than n+n which is better…
>   (sorry for delay in reply, I was on vacation).
>
>   Thanks for what might help. I was kind of expecting
>   this when preliminary patch was sent before. Let me
>   try what you suggest and send out v3.
>
>   I was also thinking if this should be inside kernel
>   facilitated by a new ioctl? so that we avoid number
>   of search ioctl thats required.
Yeah, adding another ioctl maybe help. Anyway, there is another question.
Did we need to consider metadata into subvolume's sole size?

Personaly, the answer is yes. Considering a subvolume is filled with a lot
of empty files, but we get subvolume's sole size *0*.


Thanks,
Wang
>
> Thanks, Anand
>
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