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From: Chris Murphy <lists@colorremedies.com>
Date: Mon, 27 Mar 2017 15:11:34 -0600
Message-ID: <CAJCQCtTOX6p03hPi6CJyzPKmFQMfP4oSCzbrkjftU=Sm9LdjPA@mail.gmail.com>
Subject: Re: Qgroups are not applied when snapshotting a subvol?
To: Hans van Kranenburg <hans.van.kranenburg@mendix.com>
Cc: Roman Mamedov <rm@romanrm.net>, Chris Murphy <lists@colorremedies.com>,
        "Austin S. Hemmelgarn" <ahferroin7@gmail.com>,
        Moritz Sichert <moritz+linux@sichert.me>,
        Qu Wenruo <quwenruo@cn.fujitsu.com>,
        Andrei Borzenkov <arvidjaar@gmail.com>,
        Btrfs BTRFS <linux-btrfs@vger.kernel.org>
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On Mon, Mar 27, 2017 at 2:06 PM, Hans van Kranenburg
<hans.van.kranenburg@mendix.com> wrote:
> On 03/27/2017 09:53 PM, Roman Mamedov wrote:
>> On Mon, 27 Mar 2017 13:32:47 -0600
>> Chris Murphy <lists@colorremedies.com> wrote:
>>
>>> How about if qgroups are enabled, then non-root user is prevented from
>>> creating new subvolumes?
>>
>> That sounds like, if you turn your headlights on in a car, then in-vehicle air
>> conditioner randomly stops working. :)
>>
>> Two things only vaguely related from the end user's point of view.
>>
>>> Or is there a way for a new nested subvolume to be included in its
>>> parent's quota, rather than the new subvolume having a whole new quota
>>> limit?
>>
>> Either that, or a separate "allow non-root user subvolumes/snapshots creation"
>> mount option. There is already one for deletion, after all.
>>
>>        user_subvol_rm_allowed
>>               Allow subvolumes to be deleted by a  non-root  user.   Use  with
>>               caution.
>>
>
> What are actual use cases for creating subvolumes by 'normal' users?
>
> Does someone have an example?
>
> Why is it possible at all, by default?

I have a single git subvolume in my user directory, inside of which
are various git clones. And I periodically snapshot the git subvolume
as a regular user.

If I can't create subvolumes as a regular user then by extension it'd
mean I can't create snapshots of my own home directory, or any other
subvolumes I exclusively own.

-- 
Chris Murphy