Re: find snapshot parent?

[Andrei Borzenkov <arvidjaar@gmail.com>]

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.