On Fri, Jan 15, 2021 at 02:02:36PM +0100, Alberto Garcia wrote:
> Hi,

Hi, 

> during the past months we talked about making x-blockdev-reopen stable
> API, and one of the missing things was having support for changing
> bs->file. See here for the discusssion (I can't find the message from
> Kashyap that started the thread in the web archives):
> 
>    https://lists.gnu.org/archive/html/qemu-block/2020-10/msg00922.html

Yeah, I noticed that too -- seems like it got "lost" somehow :-(.  For
the record, I've attached here the original e-mail I sent on 06-OCT-2020
that started the above thread.

Thanks for working on this!

> I was testing this and one of the problems that I found was that
> removing a filter node using this command is tricky because of the
> permission system, see here for details:
> 
>    https://lists.gnu.org/archive/html/qemu-block/2020-12/msg00092.html
> 
> The good news is that Vladimir posted a set of patches that changes
> the way that permissions are updated on reopen:
> 
>    https://lists.gnu.org/archive/html/qemu-block/2020-11/msg00745.html
> 
> I was testing if this would be useful to solve the problem that I
> mentioned earlier and it seems to be the case so I wrote a patch to
> add support for changing bs->file, along with a couple of test cases.
> 
> This is still an RFC but you can see the idea.
> 
> These patches apply on top of Vladimir's branch:
> 
> git: https://src.openvz.org/scm/~vsementsov/qemu.git
> tag: up-block-topologic-perm-v2
> 
> Opinions are very welcome!
> 
> Berto
> 
> Alberto Garcia (2):
>   block: Allow changing bs->file on reopen
>   iotests: Update 245 to support replacing files with x-blockdev-reopen
> 
>  include/block/block.h      |  1 +
>  block.c                    | 61 ++++++++++++++++++++++++++++++++++++++
>  tests/qemu-iotests/245     | 61 +++++++++++++++++++++++++++++++++++---
>  tests/qemu-iotests/245.out |  4 +--
>  4 files changed, 121 insertions(+), 6 deletions(-)
> 
> -- 
> 2.20.1
> 

-- 
/kashyap