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Date: Mon, 17 Jan 2011 11:28:47 +0000
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Subject: Re: [Qemu-devel] [PATCH 1/3] block: add resize monitor command
From: Stefan Hajnoczi <stefanha@gmail.com>
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To: Christoph Hellwig <hch@lst.de>
Cc: qemu-devel@nongnu.org

On Fri, Jan 14, 2011 at 4:20 PM, Christoph Hellwig <hch@lst.de> wrote:
> +STEXI
> +@item resize
> +@findex resize
> +Resize a block image while a guest is running. =A0Usuaully requires gues=
t

s/Usuaully/Usually/

> +action to see the updated size. =A0Resize to a lower size is supported,
> +but should be used with extreme caution.

This resizes the image files.  Resizing an LVM volume is a useful case
too.  One way to integrate that feature is to implement a host_device
.bdrv_truncate() that checks the underlying device size and returns
success if it matches the new value and failure otherwise.  Or perhaps
allow the QEMU resize command without an argument to fetch the size
from the underlying device (aka refresh the size).

> + =A0 =A0if (bdrv_get_type_hint(bs) =3D=3D BDRV_TYPE_CDROM) {
> + =A0 =A0 =A0 =A0error_report("Can not resize CDROM devices\n");
> + =A0 =A0 =A0 =A0return -1;
> + =A0 =A0}

Hrm...BDRV_TYPE_FLOPPY probably too?

Stefan