δΊ 2013-3-13 0:16, Eric Blake ει:
On 03/12/2013 04:07 AM, Stefan Hajnoczi wrote:
On Mon, Mar 11, 2013 at 07:23:02PM +0800, Wenchao Xia wrote:
In the use of snapshot a way to retrieve related info at runtime is needed,
so this serial of patches will merge some code for qemu and qemu-img, and add
following interfaces for qemu:
Is there a reason you added the new query-images command instead of
extending BlockDeviceInfo with an ImageInfo field? Then query-block,
which is already used today, just provides ImageInfo as well.
I suggest this because it makes life easier for clients - they can issue
a single command to extract all image information. If we have two
commands they may have to invoke both and then match the results
together.
Indeed, from the libvirt perspective, I would much prefer that a single
command gives me everything, instead of having to call two commands to
build up the complete picture.
I have no special reason for new interface query-images, it just
show up during the work, and I am pretty OK to merge the information
into query-block especially when the user of it, Eric hope so. Then
the qmp interface need to designed carefully, my idea is adding an item
in BlockDeviceInfo:
{ '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".
--
Best Regards
Wenchao Xia
