Re: [libvirt] [PATCH 6/9] conf: qemu: add virtio-fs fsdriver type
On Mon, Nov 04, 2019 at 09:56:28AM +0100, Stefan Hajnoczi wrote:
On Fri, Nov 1, 2019 at 1:15 PM Ján Tomko <jtomko(a)redhat.com>
wrote:
>
> Introduce a new 'virtio-fs' driver type for filesystem.
>
> <filesystem type='mount' accessmode='passthrough'>
> <driver type='virtio-fs'/>
> <source dir='/path'/>
> <target dir='/path'/>
What happens with the target dir?
For virtio-fs, it is used the same way as with 9pfs - it is passed as
the tag and meant as a suggestion for the guest for where to mount the
filesystem.
For LXC, libvirt actually does the mounting so the target dir path is
honored.
I could use some other example in the documentation that does not look
as a path if that's too confusing. I'm not sure whether deviating
from the existing pattern and using something like:
<target tag='myfs'/>
is worth it.
virtio-fs has no way to pass the target dir into the guest.
Also, I see that the mount syntax changed from -t virtio_fs to -t
virtiofs - is that the new preferred spelling that should be preserved
here?
Out-of-band methods exist: qemu-guest-agent could be used to mount
the
file system.
Doing that automatically is out of scope of libvirt. But to allow higher
layers to do that, libvirt would need to expose the 'guest-exec'
command.
Jano
Another approach is to add a uevent to the virtiofs.ko
guest driver and let udev configuration decide what to do (e.g.
automount under /run/media/virtio-fs/$TAG or similar).
Stefan
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