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Date: Thu, 20 Jan 2011 09:14:17 +0000
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Subject: Re: [Qemu-devel] [PATCH 2/3] block: tell drivers about an image resize
From: Stefan Hajnoczi <stefanha@gmail.com>
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To: Christoph Hellwig <hch@lst.de>
Cc: qemu-devel@nongnu.org

On Wed, Jan 19, 2011 at 5:02 PM, Christoph Hellwig <hch@lst.de> wrote:
> Extend the change_cb callback with a reason argument, and use it
> to tell drivers about size changes.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
>
> Index: qemu/block.c
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> --- qemu.orig/block.c =A0 2011-01-18 20:54:45.246021572 +0100
> +++ qemu/block.c =A0 =A0 =A0 =A02011-01-18 20:56:54.117255612 +0100
> @@ -645,7 +645,7 @@ int bdrv_open(BlockDriverState *bs, cons
> =A0 =A0 =A0 =A0 /* call the change callback */
> =A0 =A0 =A0 =A0 bs->media_changed =3D 1;
> =A0 =A0 =A0 =A0 if (bs->change_cb)
> - =A0 =A0 =A0 =A0 =A0 =A0bs->change_cb(bs->change_opaque);
> + =A0 =A0 =A0 =A0 =A0 =A0bs->change_cb(bs->change_opaque, CHANGE_MEDIA);

Cool, this is much nicer than stashing away state like
bs->media_changed =3D 1.  I just took a peek to see if we can remove
that field completely but IDE seems to use it internally.

Stefan