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").
Hugo.
--
Hugo Mills | Well, you don't get to be a kernel hacker simply by
hugo@... carfax.org.uk | looking good in Speedos.
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PGP: E2AB1DE4 | Rusty Russell
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