[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] Re: [PATCH v3] qcow2: Implement bdrv_truncate() for growing
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] Re: [PATCH v3] qcow2: Implement bdrv_truncate() for growing images |
Date: |
Wed, 28 Apr 2010 14:38:32 +0200 |
User-agent: |
Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100330 Fedora/3.0.4-1.fc12 Thunderbird/3.0.4 |
Am 28.04.2010 12:36, schrieb Stefan Hajnoczi:
> This patch adds the ability to grow qcow2 images in-place using
> bdrv_truncate(). This enables qemu-img resize command support for
> qcow2.
>
> Snapshots are not supported and bdrv_truncate() will return -ENOTSUP.
> The notion of resizing an image with snapshots could lead to confusion:
> users may expect snapshots to remain unchanged, but this is not possible
> with the current qcow2 on-disk format where the header.size field is
> global instead of per-snapshot. Others may expect snapshots to change
> size along with the current image data. I think it is safest to not
> support snapshots and perhaps add behavior later if there is a
> consensus.
>
> Backing images continue to work. If the image is now larger than its
> backing image, zeroes are read when accessing beyond the end of the
> backing image.
>
> Signed-off-by: Stefan Hajnoczi <address@hidden>
Thanks, applied to the block branch.
Kevin