|
| From: | Ivan Ren |
| Subject: | Re: [Qemu-block] [Qemu-devel] [PATCH v2] qcow2: fix preallocation with metadata on bare block device |
| Date: | Fri, 11 May 2018 22:40:48 +0800 |
>> Create a qcow2 directly on bare block device with
>> "-o preallocation=metadata" option. When read this qcow2, it will
>> return pre-existing data on block device, and this may lead to
>> data leakage. This patch add QCOW_OFLAG_ZERO for all preallocated
>> l2 entry to avoid this problem.
>
> This is a semantic change; are we okay making it?
> Does your code properly check for qcow2v2 files, which don't support
> QCOW_OFLAG_ZERO (only qcow2v3 supports it)?
Sorry for this mistake.
Current solution can only be used with s->qcow_version >= 3.
I'll fix it.
On 05/11/2018 07:37 AM, Ivan Ren wrote:
> Create a qcow2 directly on bare block device with
> "-o preallocation=metadata" option. When read this qcow2, it will
> return pre-existing data on block device, and this may lead to
> data leakage. This patch add QCOW_OFLAG_ZERO for all preallocated
> l2 entry to avoid this problem.
This is a semantic change; are we okay making it?
Does your code properly check for qcow2v2 files, which don't support
QCOW_OFLAG_ZERO (only qcow2v3 supports it)?
>
> Signed-off-by: Ivan Ren <address@hidden>
> ---
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
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