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Re: [Qemu-devel] [PATCH V9 00/14] qmp/hmp interfaces for internal snapsh
From: |
Eric Blake |
Subject: |
Re: [Qemu-devel] [PATCH V9 00/14] qmp/hmp interfaces for internal snapshot info |
Date: |
Wed, 13 Mar 2013 06:29:18 -0600 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130219 Thunderbird/17.0.3 |
On 03/13/2013 05:34 AM, Stefan Hajnoczi wrote:
>>
>> { 'type': 'BlockDeviceInfo',
>> 'data': { 'file': 'str', 'ro': 'bool', 'drv': 'str',
>> '*backing_file': 'str', 'backing_file_depth': 'int',
>> 'encrypted': 'bool', 'encryption_key_missing': 'bool',
>> 'bps': 'int', 'bps_rd': 'int', 'bps_wr': 'int',
>> 'iops': 'int', 'iops_rd': 'int', 'iops_wr': 'int',
>> 'images': ['ImageInfo']} }}
>>
>> In this way, new define of structure is not needed, and no break
>> of API I guess, but disadvantage is there will be some duplicated info
>> in ImageInfo and other structure in BlockInfo, such as "file,
>> encrypted".
>
> I'm happy with adding a ImageInfo field into BlockDeviceInfo.
>
> Why did you make it an array and what is the array's layout?
I think the point of an array of ImageInfo is to let us return data on
an entire backing chain. That is, if I have:
image.raw <- middle.qcow2 (with internal snapshot "a") <- top.qcow2
(with internal snapshots "b", "c")
then I want to see data on image.raw, as well as on snapshots a, b, and
c, all in one command. For my example, 'images' would be a
three-element array, with element 0 describing top.qcow2 and its two
internal snapshots, element 1 describing middle.qcow2 and its snapshot,
and element 2 describing image.raw.
However, it's also worth remembering that there has been a proposal for
having quorums, where a single block device can have multiple images
associated with the top level, and where we would then want a recursive
structure rather than an array for representing backing chain
information of a given information within the array of multiple images
associated with a single quorum device.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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- Re: [Qemu-devel] [PATCH V9 08/14] qmp: add interface query-snapshots, (continued)
- [Qemu-devel] [PATCH V9 11/14] hmp: switch snapshot info function to qmp based one, Wenchao Xia, 2013/03/11
- [Qemu-devel] [PATCH V9 12/14] block: move dump_human_image_info() to block/qapi.c, Wenchao Xia, 2013/03/11
- [Qemu-devel] [PATCH V9 14/14] hmp: add command info images, Wenchao Xia, 2013/03/11
- [Qemu-devel] [PATCH V9 13/14] block: dump to buffer for bdrv_image_info_dump(), Wenchao Xia, 2013/03/11
- Re: [Qemu-devel] [PATCH V9 00/14] qmp/hmp interfaces for internal snapshot info, Stefan Hajnoczi, 2013/03/12
- Re: [Qemu-devel] [PATCH V9 00/14] qmp/hmp interfaces for internal snapshot info, Eric Blake, 2013/03/12
- Re: [Qemu-devel] [PATCH V9 00/14] qmp/hmp interfaces for internal snapshot info, Wenchao Xia, 2013/03/12
- Re: [Qemu-devel] [PATCH V9 00/14] qmp/hmp interfaces for internal snapshot info, Stefan Hajnoczi, 2013/03/13
- Re: [Qemu-devel] [PATCH V9 00/14] qmp/hmp interfaces for internal snapshot info,
Eric Blake <=
- Re: [Qemu-devel] [PATCH V9 00/14] qmp/hmp interfaces for internal snapshot info, Kevin Wolf, 2013/03/13
- Re: [Qemu-devel] [PATCH V9 00/14] qmp/hmp interfaces for internal snapshot info, Stefan Hajnoczi, 2013/03/13
- Re: [Qemu-devel] [PATCH V9 00/14] qmp/hmp interfaces for internal snapshot info, Wenchao Xia, 2013/03/15
- Re: [Qemu-devel] [PATCH V9 00/14] qmp/hmp interfaces for internal snapshot info, Kevin Wolf, 2013/03/15
- Re: [Qemu-devel] [PATCH V9 00/14] qmp/hmp interfaces for internal snapshot info, Wenchao Xia, 2013/03/18
- Re: [Qemu-devel] [PATCH V9 00/14] qmp/hmp interfaces for internal snapshot info, Kevin Wolf, 2013/03/18
- Re: [Qemu-devel] [PATCH V9 00/14] qmp/hmp interfaces for internal snapshot info, Stefan Hajnoczi, 2013/03/15