Re: [libvirt] [PATCH] Add basic support for VDI images
On 02/04/2013 04:53 PM, Daniel P. Berrange wrote:
On Mon, Feb 04, 2013 at 04:46:53PM +0100, Martin Kletzander wrote:
[...]
> +
> + /* not fully supported, but qemu knows it, so we should be able to
> + * handle this at least basically */
> + [VIR_STORAGE_FILE_VDI] = { NULL, ".vdi", LV_LITTLE_ENDIAN,
> + -2, 0, 0, 0, 0, -1, NULL},
We can do better than that - look at block/vdi.c in QEMU GIT tree
to find out the offsets / values for version number, magic signature
at least, even if you ignore backing files for now.
Thanks for pointing that out, I've got a v2 and will send it
after some testing. However, it looks like VDI doesn't have a
magic, because there is a 40 Byte string at the start that cacn
contain anything the creating binary puts there. For example
qemu-img uses "<<< QEMU VM Virtual Disk Image >>>\n".
According
to [1], I'm adding "<<<" as the magic, because we don't fail
if
it doesn't match and we can still match it by the extension then.
[1] Cite from block/vdi.c:
/* Innotek / SUN images use these strings in header.text:
* "<<< innotek VirtualBox Disk Image >>>\n"
* "<<< Sun xVM VirtualBox Disk Image >>>\n"
* "<<< Sun VirtualBox Disk Image >>>\n"
* The value does not matter, so QEMU created images use a different text.
*/
#define VDI_TEXT "<<< QEMU VM Virtual Disk Image >>>\n"
I added all the rest I could, though.
Martin