Re: generic name for volume and subvolume root?

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

On 09/09/2017 01:06 PM, Hugo Mills wrote:
> On Sat, Sep 09, 2017 at 06:58:38PM +0800, Qu Wenruo wrote:
>>
>>
>> On 2017年09月09日 18:48, Ulli Horlacher wrote:
>>> On Sat 2017-09-09 (18:40), Qu Wenruo wrote:
>>>
>>>>> Is there a generic name for both volume and subvolume root?
>>>>
>>>> Nope, subvolume (including snapshot) is not distinguished by its
>>>> filename/path/directory name.
>>>>
>>>> And you can only do snapshot on subvolume (snapshot is one kind of
>>>> subvolume) boundary.
>>>
>>> So, I can name a btrfs root volume also btrfs subvolume?
>>
>> Yes, root volume is also a subvolume, so just call "btrfs root volume"
>> a "subvolume".
> 
>    I find it's best to avoid the word "root" entirely, as it's got
> several meanings, and it tends to get confusing in conversation.
> Instead, we have:
> 
>  - "the top level" (subvolid=5)
>  - "/"             (what you see at / in your running system)
>  - "<top-level>/@" or similar names
>                    (the subvolume that's mounted at /)
> 
>>> I am talking about documentation, not coding!
>>>
>>> I just want yo use the correct terms.
>>
>> If you're referring to the term, I think subvolume is good enough.
>> Which represents your original term, "directories one can snapshot".
>>
>>
>> For the whole btrfs "volume", I would just call it "filesystem" to
>> avoid the name "volume" or "subvolume" at all.
> 
>    Yes, it's a filesystem. (Although that does occasionally cause
> confusion between "the conceptual filesystem implemented by btrfs.ko"
> and "the concrete filesystem stored on /dev/sda1", but it's generally
> far less confusing than the overloading of "root").

Yes, because every subvolume is a filesystem root! :-D

https://i.imgur.com/2VzmC.gif

-- 
Hans van Kranenburg