Re: [Qemu-devel] [PATCH 00/15] block: Overriding the backing file with -drive

[Stefan Hajnoczi]

On Fri, Apr 12, 2013 at 10:47:53PM +0200, Kevin Wolf wrote:
> This is the next part of the driver-specific options. Looks like we're getting
> closer to pass file descriptors for the whole backing file chain. In fact, I
> hope we're now only lacking QMP support before we can actually use it. :-)
> 
> This series adds support for the backing.* options namespace, and allows to 
> use
> the file.filename option to configure the filename string for non-top-level
> BlockDriverStates. In the end you can use things like:
> 
>     -drive file=test.qcow2,backing.file.filename=/dev/fdset/1,
>     backing.backing.file.driver=nbd,backing.backing.file.host=localhost

Nice series.

> On another note, I'm still not sure whether I should leave all of this work
> enabled for 1.5, or if we wouldn't be better off with disabling it for the
> release so that we have some additional months before we commit to the
> interface. Any opinions?

I suggest we leave this series and the io_flush series I sent recently
out of QEMU 1.5.  Once they are reviewed, let's merge them into
block-next.  When 1.6 opens they'll be the first things to get merged.

Unless there's an urgent need to get this into 1.5, I don't see the big
win - QMP changes are still missing anyway.  Let's not rush it.

Also, I guess documentation changes are missing to really make this
feature ready for end-users :).

Stefan