[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH] vhdx: Return true for bdrv_has_zero_init
From: |
Jeff Cody |
Subject: |
Re: [Qemu-devel] [PATCH] vhdx: Return true for bdrv_has_zero_init |
Date: |
Fri, 5 Dec 2014 09:35:38 -0500 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Fri, Dec 05, 2014 at 12:07:19PM +0100, Kevin Wolf wrote:
> 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?
>
Yes, I'll go ahead and put together a patch(es) for that.