[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-block] [Qemu-devel] [PATCH 1/2] commit: Add top-node/base-node

From: Peter Krempa
Subject: Re: [Qemu-block] [Qemu-devel] [PATCH 1/2] commit: Add top-node/base-node options
Date: Tue, 28 Aug 2018 16:26:26 +0200
User-agent: Mutt/1.9.3 (2018-01-21)

On Fri, Aug 10, 2018 at 18:26:57 +0200, Kevin Wolf wrote:
> The block-commit QMP command required specifying the top and base nodes
> of the commit jobs using the file name of that node. While this works
> in simple cases (local files with absolute paths), the file names
> generated for more complicated setups can be hard to predict.
> This adds two new options top-node and base-node to the command, which
> allow specifying node names instead. They are mutually exclusive with
> the old options.
> Signed-off-by: Kevin Wolf <address@hidden>
> ---
>  qapi/block-core.json | 24 ++++++++++++++++++------
>  blockdev.c           | 32 ++++++++++++++++++++++++++++++--
>  2 files changed, 48 insertions(+), 8 deletions(-)

While the below is not strictly relevant to this patch usage
block-commit is not possible when using -blockdev. Thus the new
arguments are not very useful otherwise.

With the new options I'm getting:

 "arguments": { "device":"libvirt-3-format",

          "desc":"Block node is read-only"}}

I'm pointing into the backing chain so the files are declared as read-only.

It works just-fine if I open them as read-write with
-blockdev/blockdev-add but that obviously is not correct as you can't
then share parts of the backing chain with other VMs due to image

libvirt-3-format is read-write and all other node names are readonly in
the above example.

The same also happens when using filenames:

 "arguments" : {"device":"libvirt-3-format",

{"id":"libvirt-13","error":{"class":"GenericError","desc":"Block node is 

When I use the drive alias rather than the node-name for the 'device'
argument it works as expected.

 "arguments": { "device":"drive-virtio-disk0",

I was not able to find anything which would allow to reopen the file R/W
in case of the block-commit operation, but I suspect it should be done
automatically as previously it was done that way prior to -blockdev.


Attachment: signature.asc
Description: PGP signature

reply via email to

[Prev in Thread] Current Thread [Next in Thread]