Re: bug? fstrim only trims unallocated space, not unused in bg's

[Jeff Mahoney <jeffm@suse.com>]

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On 11/20/17 3:00 PM, Jeff Mahoney wrote:
> On 11/19/17 4:38 PM, Chris Murphy wrote:
>> On Sat, Nov 18, 2017 at 11:27 PM, Andrei Borzenkov <arvidjaar@gmail.com> wrote:
>>> 19.11.2017 09:17, Chris Murphy пишет:
>>>> fstrim should trim free space, but it only trims unallocated. This is
>>>> with kernel 4.14.0 and the entire 4.13 series. I'm pretty sure it
>>>> behaved this way with 4.12 also.
>>>>
>>>
>>> Well, I was told it should also trim free space ...
>>>
>>> https://www.spinics.net/lists/linux-btrfs/msg61819.html
>>>
>>
>> It definitely isn't. If I do a partial balance, then fstrim, I get a
>> larger trimmed value, corresponding exactly to unallocated space.
> 
> 
> I've just tested with 4.14 and it definitely trims within block groups.

Derp.  This should read 4.12.

> I've attached my test script and the log of the run.  I'll build and
> test a 4.14 kernel and see if I can reproduce there.  It may well be
> that we're just misreporting the bytes trimmed.
> 
> -Jeff
> 
> 


-- 
Jeff Mahoney
SUSE Labs


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