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Re: [PATCH] ovl: do not ignore disk quota if current task is not privileged

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On 10.01.2017 19:35, Vivek Goyal wrote:
> On Tue, Jan 10, 2017 at 11:06:47AM -0500, Vivek Goyal wrote:
>> On Tue, Jan 10, 2017 at 02:26:48PM +0300, Konstantin Khlebnikov wrote:
>>> If overlay was mounted by root then quota set for upper layer does not work
>>> because overlay now always use mounter's credentials for operations.
>>>
>>
>> Hi Konstantin,
>>
>> So CAP_SYS_RESOURCE bypasses the quota checks?
>>
>> I just created dir upper on xfs filesystem and defined quota of 1G and
>> as root user (with cap_sys_resoureces), I am not able to create file
>> bigger than 1g in that dir. So looks like xfs quota took affect even
>> for privileged user with CAP_SYS_RESOURCE set.
>>
>> What am I missing?
>
> As root user, I set limit of 1G on work/ and upper/ dir and created
> a file of 4G in lower/ dir and mounted overlay on "merged" dir and
> did "touch zerofile", and go error message.
>
> touch: cannot touch 'zerofile': No space left on device
>
> So looks like I am doing something wrong and not be able to reproduce
> the issue to begin with.
>

I'm using ext4 project quota around upper/work directories.
ext4 use generic quota implementation: it ignores hard limits if CAP_SYS_RESOURCE is set.

It seems XFS ignores CAP_SYS_RESOURCE for any kind of quota.
But I've found special meaning for CAP_FOWNER - chown() can ignore user/group
quota if caller have this capability.

-- 
Konstantin

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Thread

[PATCH] ovl: do not ignore disk quota if current task is not  privileged Konstantin Khlebnikov <khlebnikov@yandex-team.ru> - 2017-01-10 12:40 +0100
  Re: [PATCH] ovl: do not ignore disk quota if current task is not  privileged Vivek Goyal <vgoyal@redhat.com> - 2017-01-10 15:50 +0100
    Re: [PATCH] ovl: do not ignore disk quota if current task is not privileged Miklos Szeredi <miklos@szeredi.hu> - 2017-01-10 17:00 +0100
      Re: [PATCH] ovl: do not ignore disk quota if current task is not  privileged Konstantin Khlebnikov <khlebnikov@yandex-team.ru> - 2017-01-10 17:40 +0100
        Re: [PATCH] ovl: do not ignore disk quota if current task is not privileged Amir Goldstein <amir73il@gmail.com> - 2017-01-10 19:20 +0100
          Re: [PATCH] ovl: do not ignore disk quota if current task is not  privileged Konstantin Khlebnikov <khlebnikov@yandex-team.ru> - 2017-01-10 19:40 +0100
  Re: [PATCH] ovl: do not ignore disk quota if current task is not  privileged Vivek Goyal <vgoyal@redhat.com> - 2017-01-10 17:10 +0100
    Re: [PATCH] ovl: do not ignore disk quota if current task is not  privileged Vivek Goyal <vgoyal@redhat.com> - 2017-01-10 17:40 +0100
      Re: [PATCH] ovl: do not ignore disk quota if current task is not  privileged Konstantin Khlebnikov <khlebnikov@yandex-team.ru> - 2017-01-10 17:50 +0100
    Re: [PATCH] ovl: do not ignore disk quota if current task is not  privileged Konstantin Khlebnikov <khlebnikov@yandex-team.ru> - 2017-01-10 17:40 +0100
  [PATCH v2] ovl: drop CAP_SYS_RESOURCE from saved mounter's  credentials Konstantin Khlebnikov <khlebnikov@yandex-team.ru> - 2017-01-10 19:40 +0100
    Re: [PATCH v2] ovl: drop CAP_SYS_RESOURCE from saved mounter's  credentials Vivek Goyal <vgoyal@redhat.com> - 2017-01-10 20:20 +0100

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