[libvirt] [PATCH 3/4] Fix QEMU save/restore with block devices

Daniel Veillard veillard at redhat.com
Thu Apr 22 12:00:56 UTC 2010

On Thu, Apr 22, 2010 at 12:43:28PM +0100, Daniel P. Berrange wrote:
> The save process was relying on use of the shell >> append
> operator to ensure the save data was placed after the libvirt
> header + XML. This doesn't work for block devices though.
> Replace this code with use of 'dd' and its 'seek' parameter.
> This means that we need to pad the header + XML out to a
> multiple of dd block size (in this case we choose 512).

  err, why ? As I pointed out dd seems just fine taking byte specified
offset, not necessarilly multiple of 512. The main problem I see with
this is that it does break the format and a somain saved (or managed
save) with 0.8.0 would not restore with 0.8.1.
  I really want to understand why this is needed before going that route
because I see this as a serious compatibility break.


Daniel Veillard      | libxml Gnome XML XSLT toolkit  http://xmlsoft.org/
daniel at veillard.com  | Rpmfind RPM search engine http://rpmfind.net/
http://veillard.com/ | virtualization library  http://libvirt.org/

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