Re: subvolume list as user?

[Hans van Kranenburg <hans.van.kranenburg@mendix.com>]

On 09/16/2017 11:45 AM, Ulli Horlacher wrote:
> Every user can create subvolumes (and root cannot prevent it!).
> But how can a user list these subvolumes?
> 
> tux@xerus:/test/tux: btrfs subvolume create test
> Create subvolume './test'

>From your other posts I don't quickly get if you actually do want to
have this possible, or accept that it's currently like that and try to
do damage control by having users also remove their things again.

Actually, if you don't want this I think it's quite easily to patch your
kernel with one or two lines of code to disallow it.

> tux@xerus:/test/tux: btrfs subvolume list .
> ERROR: can't perform the search - Operation not permitted

Yes, because the SEARCH ioctl only allows root to directly query any of
the filesystem metadata from kernel memory. subvolume list uses this
SEARCH ioctl to find it's info.

-- 
Hans van Kranenburg