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Re: [Qemu-devel] format=raw,readonly errors
From: |
Max Reitz |
Subject: |
Re: [Qemu-devel] format=raw,readonly errors |
Date: |
Mon, 8 May 2017 18:47:31 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.0.1 |
On 08.05.2017 18:33, Carl Karsten wrote:
> On Mon, May 8, 2017 at 11:29 AM, Eric Blake <address@hidden> wrote:
>
>> On 05/08/2017 10:56 AM, Carl Karsten wrote:
>>
>>>>>>> address@hidden:~/temp$ qemu-system-x86_64 -m 256 -display curses
>> -drive
>>>>>>> file=disk.cow -drive file=boot.img
>>>>>>> WARNING: Image format was not specified for 'boot.img' and probing
>>>>>> guessed
>>>>>>> raw.
>>>>>>> Automatically detecting the format is dangerous for raw
>>>> images,
>>>>>>> write operations on block 0 will be restricted.
>>>>>>> Specify the 'raw' format explicitly to remove the
>>>> restrictions.
>>
>>> "write operations on block 0 will be restricted."
>>>
>>> Is there a way to explicitly enable that?
>>
>> Yes. Pass format=raw at the right place (in other words, instead of
>> getting the 'raw' format driver by default, explicitly mentioning that
>> you KNOW you want the 'raw' format driver is enough to shut up the
>> warning).
>>
>
> according to the warning: "Specify the 'raw' format explicitly to remove
> the restrictions."
>
> I want the restriction.
>
> format=raw, (write operations on block 0)=restricted
Well, the restriction won't prevent all writes to the first sector,
though; it will only prevent writes which would make the image look like
it was in some non-raw format. So this is probably not what you want anyway.
Unfortunately, I don't know any current way to "soft" write-protect an
image. It sounds like an interesting idea, though, and should be simple
enough to implement e.g. in the raw driver.
Max
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- [Qemu-devel] format=raw,readonly errors, Carl Karsten, 2017/05/08
- Re: [Qemu-devel] format=raw,readonly errors, Markus Armbruster, 2017/05/08
- Re: [Qemu-devel] format=raw,readonly errors, Carl Karsten, 2017/05/08
- Re: [Qemu-devel] format=raw,readonly errors, John Snow, 2017/05/08
- Re: [Qemu-devel] format=raw,readonly errors, Carl Karsten, 2017/05/08
- Re: [Qemu-devel] format=raw,readonly errors, Eric Blake, 2017/05/08
- Re: [Qemu-devel] format=raw,readonly errors, Carl Karsten, 2017/05/08
- Re: [Qemu-devel] format=raw,readonly errors, Eric Blake, 2017/05/08
- Re: [Qemu-devel] format=raw,readonly errors, Eric Blake, 2017/05/08
- Re: [Qemu-devel] format=raw,readonly errors,
Max Reitz <=
- Re: [Qemu-devel] format=raw,readonly errors, Daniel P. Berrange, 2017/05/08