Re: virtiofsd: Where should it live?

[Marc-André Lureau]

Hi David

On Mon, Nov 25, 2019 at 10:50 PM Dr. David Alan Gilbert
<address@hidden> wrote:
>
> Hi,
>   There's been quite a bit of discussion about where virtiofsd, our
> implemenation of a virtiofs daemon, should live.  I'd like to get
> this settled now, because I'd like to tidy it up for the next
> qemu cycle.
>
> For reference it's based on qemu's livhost-user+chunks of libfuse.
> It can't live in libfuse because we change enough of the library
> to break their ABI.  It's C, and we've got ~100 patches - which
> we can split into about 3 chunks.
>
> Some suggestions so far:
>   a) In contrib
>      This is my current working assumption; the main objection is it's
>      a bit big and pulls in a chunk of libfuse
>
>   b) In a submodule
>
>   c) Just separate
>
> Your suggestions/ideas please.  My preference is (a).
>


It's more about code sharing and lifecycle.

The project started in a separate repository, and the proposed patches
for qemu aren't a clean series. Reviewing it is harder than it should
be, as we have to review/accept the whole thing.

As you said, it doesn't share much with qemu, but libvhost-user (which
we could quite easily copy or make standalone/submodule).

Then it dumps code from libfuse that is questionnable (showing age)
and often redundant with facilities provided by either glib, qemu
utils etc.

Is vhost-user-fs (the qemu device) going to have a strong relation
with virtiofsd?
Are we going to support different version of qemu and virtiofsd
combination? I suppose we have to, as vhost-user protocol should allow
that, and it's nice to allow other to experiment and implement it in
different ways.
If not, then perhaps we should think about introducing some version
checking between qemu and external processes (with config_stamp,
similar to modules).

>From what I understand, I think c) would be fine. However, for
convenience/testing reasons, b) would be my preference.

-- 
Marc-André Lureau