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Re: [Qemu-devel] [PATCH 09/21] qcow2: Open images with refcount order !=
From: |
Eric Blake |
Subject: |
Re: [Qemu-devel] [PATCH 09/21] qcow2: Open images with refcount order != 4 |
Date: |
Mon, 10 Nov 2014 10:03:23 -0700 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 |
On 11/10/2014 06:45 AM, Max Reitz wrote:
> No longer refuse to open images with a different refcount entry width
> than 16 bits; only reject images with a refcount width larger than 64
> bits (which is prohibited by the specification).
>
> Signed-off-by: Max Reitz <address@hidden>
> ---
> block/qcow2.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/block/qcow2.c b/block/qcow2.c
> index d70e927..b718e75 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -677,10 +677,10 @@ static int qcow2_open(BlockDriverState *bs, QDict
> *options, int flags,
> }
>
> /* Check support for various header values */
> - if (header.refcount_order != 4) {
> - report_unsupported(bs, errp, "%d bit reference counts",
> - 1 << header.refcount_order);
> - ret = -ENOTSUP;
> + if (header.refcount_order > 6) {
> + error_setg(errp, "Reference count entry width too large (%i bit);
> may "
> + "not exceed 64 bit", 1 << header.refcount_order);
Overflows if I fuzz an image to put 32 or larger into
header.refcount_order. It may be better to just tweak the error message
to state that the order cannot exceed 6, rather than trying to display
the actual bit width that the user is requesting, as then you avoid the
'1 << problem'.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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- Re: [Qemu-devel] [PATCH 05/21] qcow2: Refcount overflow and qcow2_alloc_bytes(), (continued)
[Qemu-devel] [PATCH 07/21] qcow2: Helper for refcount array size calculation, Max Reitz, 2014/11/10
[Qemu-devel] [PATCH 08/21] qcow2: More helpers for refcount modification, Max Reitz, 2014/11/10
[Qemu-devel] [PATCH 09/21] qcow2: Open images with refcount order != 4, Max Reitz, 2014/11/10
- Re: [Qemu-devel] [PATCH 09/21] qcow2: Open images with refcount order != 4,
Eric Blake <=
[Qemu-devel] [PATCH 10/21] qcow2: refcount_order parameter for qcow2_create2, Max Reitz, 2014/11/10
[Qemu-devel] [PATCH 06/21] qcow2: Helper function for refcount modification, Max Reitz, 2014/11/10
[Qemu-devel] [PATCH 11/21] iotests: Prepare for refcount_width option, Max Reitz, 2014/11/10