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Re: [Qemu-devel] [PATCH v14 11/14] qemu-img: Specify backing file for co
From: |
Eric Blake |
Subject: |
Re: [Qemu-devel] [PATCH v14 11/14] qemu-img: Specify backing file for commit |
Date: |
Fri, 24 Oct 2014 10:23:05 -0600 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 |
On 10/24/2014 07:57 AM, Max Reitz wrote:
> Introduce a new parameter for qemu-img commit which may be used to
> explicitly specify the backing file into which an image should be
> committed if the backing chain has more than a single layer.
>
> Signed-off-by: Max Reitz <address@hidden>
> ---
> qemu-img-cmds.hx | 4 ++--
> qemu-img.c | 32 +++++++++++++++++++++++---------
> qemu-img.texi | 12 +++++++++++-
> 3 files changed, 36 insertions(+), 12 deletions(-)
>
> +If the backing chain of the given image file @var{filename} has more than one
> +layer, the backing file into which the changes will be committed may be
> +specified as @var{base} (which has to be part of @var{filename}'s backing
> +chain). If @var{base} is not specified, the immediate backing file of the top
> +image (which is @var{filename}) will be used. For reasons of consistency,
> +explicitly specifying @var{base} will always imply @code{-d} (otherwise, an
> +image could be committed in an indirect backing file and emptying it might
> lead
> +to different data being read from it because the intermediate backing chain
> +overrules the commit target).
I wonder if there is any better wording to make it obvious that both
instances of 'it' in the (comment) refer to the further reference of the
top image, and not the closer reference to the indirect backing file. Maybe:
...always imply -d (since emptying an image after committing to an
indirect backing file would lead to different data being read from the
image due to content in the intermediate backing chain overruling the
commit target)
But I can live with the wording as you proposed it, so:
Reviewed-by: Eric Blake <address@hidden>
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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- [Qemu-devel] [PATCH v14 04/14] blockjob: Introduce block_job_complete_sync(), (continued)
- [Qemu-devel] [PATCH v14 04/14] blockjob: Introduce block_job_complete_sync(), Max Reitz, 2014/10/24
- [Qemu-devel] [PATCH v14 06/14] iotests: Omit length/offset test in 040 and 041, Max Reitz, 2014/10/24
- [Qemu-devel] [PATCH v14 05/14] blockjob: Add "ready" field, Max Reitz, 2014/10/24
- [Qemu-devel] [PATCH v14 07/14] block/mirror: Improve progress report, Max Reitz, 2014/10/24
- [Qemu-devel] [PATCH v14 08/14] qemu-img: Implement commit like QMP, Max Reitz, 2014/10/24
- [Qemu-devel] [PATCH v14 09/14] qemu-img: Empty image after commit, Max Reitz, 2014/10/24
- [Qemu-devel] [PATCH v14 10/14] qemu-img: Enable progress output for commit, Max Reitz, 2014/10/24
- [Qemu-devel] [PATCH v14 11/14] qemu-img: Specify backing file for commit, Max Reitz, 2014/10/24
- Re: [Qemu-devel] [PATCH v14 11/14] qemu-img: Specify backing file for commit,
Eric Blake <=
- [Qemu-devel] [PATCH v14 13/14] iotests: Add test for backing-chain commits, Max Reitz, 2014/10/24
- [Qemu-devel] [PATCH v14 12/14] iotests: Add _filter_qemu_img_map, Max Reitz, 2014/10/24
- [Qemu-devel] [PATCH v14 14/14] iotests: Add test for qcow2's bdrv_make_empty, Max Reitz, 2014/10/24
- Re: [Qemu-devel] [PATCH v14 00/14] qemu-img: Implement commit like QMP, Kevin Wolf, 2014/10/28
- Re: [Qemu-devel] [PATCH v14 00/14] qemu-img: Implement commit like QMP, Stefan Hajnoczi, 2014/10/29