Re: [Qemu-devel] [PATCH] vhdx: Return true for bdrv_has_zero_init

[Kevin Wolf]

Am 05.12.2014 um 11:26 hat Kevin Wolf geschrieben:
> Like for most other image formats, vhdx images read as all zero in qemu
> after their creation (we're taking advantage from the fact that qemu has
> just created the image, because PAYLOAD_BLOCK_NOT_PRESENT actually means
> undefined rather than zeroed according to the spec).

Brain fart, self-NACK.

This obviously means that 'qemu-img convert' still can't leave zeros in
the source file unwritten in the destination, otherwise we're corrupting
data. qemu would still read them correctly, but other implementations
might not.

We'd have to write the BAT for dynamic images with PAYLOAD_BLOCK_ZERO
for all clusters before we can make this change.

Jeff, do you want to fix this?

Kevin