[libvirt] [PATCH]: Export the 'label' on block devices

Chris Lalancette clalance at redhat.com
Thu Oct 16 09:34:51 UTC 2008

Daniel Veillard wrote:
>   Patch looks fine to me +1
>   I wonder what happens when you hit a block device which had no label
> or  partition table, and has a raw file system on it directly. I
> sometimes do that by mistake on USB devices but the kernel still manage
> to handle them ... sometimes.

Yeah, interesting point.  In a quick test, formatting it with ext3 left the
entire first 1KB full of zeros, so that would just show up as "unknown".
Formatting as msdos put the "0x55AA" signature at the exact same place as the
partition table would, so you would get a false positive there.  I don't think
that's a huge issue, though; trying to do further operations (like actually
reading the partition table) are going to just not work.

In general, you can definitely craft a partition table that will fool this code.
 But further operations will fail, so you will still get error reporting, just
delayed error reporting.

Chris Lalancette

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