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

[Anand Jain <Anand.Jain@oracle.com>]

On 10/07/2013 11:01 AM, Wang Shilong wrote:
> 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*.


 yes. Will consider for an update patch later.


Thanks, Anand