[pve-devel] Make check for linked clones more nuanced

[Thomas Lamprecht]

On 6/7/18 2:34 PM, Wolfgang Link wrote:
> Qemu can use qcow2 format to make linked clones.
> LXC we do not have this, and so there is no way to make
> linked clone on directory storage.
> 
> With the 'lxc_clone' feature property we can distinguish between
> LXC and QEMU.
> 

I'm objecting calling it lxc_clone, if we introduce it, either
linkedclone (lclone /maybe/). We want to try to be as general as
possible in pve-storage, it shouldn't care much in it's plugins
feature list which specific technology action (e.g., cloning lxc)
can be done on a storage type, but rather _what_ that action
actually does, or needs to do. And that should be used as name.

But actually the problem could be that we say in the directory
base plugins volume_has_feature method that they can clone raw
images. But they can only fully clone (= copy) it??
And for that the 'copy' feature is already there...
So the question is if the raw format should, and more important
_could_, be removed from directory based storage plugins clone
feature?

I do not want to add extra specialized features if we can avoid
it and without good understanding why it's needed.

cheers,
Thomas