Re: find snapshot parent?

Andrei Borzenkov
2019-07-07T05:28:13Z

06.07.2019 23:43, Ulli Horlacher пишет:
> On Sat 2019-07-06 (19:57), Nikolay Borisov wrote:
>
>>> And how can I see whether /test/tmp/xx/ss1 is a snapshot at all?
>>> Do all snapshots have a "Parent UUID" and regular subvolumes not?
>>
>> Indeed, only snapshots have a Parent UUID.
>
> Not all:
>
> root@xerus:/test# btrfs subvolume snapshot -r /test /test/ss1
> Create a readonly snapshot of '/test' in '/test/ss1'
>
> root@xerus:/test# btrfs subvolume show /test/ss1
> /test/ss1
> Name: ss1
> UUID: 02bd07bc-0bab-3442-96be-40790e1ba9be
> Parent UUID: -
> Received UUID: -
> Creation time: 2019-07-06 22:37:37 +0200
> Subvolume ID: 1036
> Generation: 9824
> Gen at creation: 9824
> Parent ID: 5
> Top level ID: 5
> Flags: readonly
> Snapshot(s):
>
> root@xerus:/test# btrfs subvolume show /test
> /test is toplevel subvolume
>

Which is one more reason to not use btrfs top level directly.