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Date: Wed, 13 Aug 2008 21:53:39 +0300
From: Gleb Natapov <gleb@qumranet.com>
Subject: Re: [Qemu-devel] [PATCH] Flush pending AIO on reboot and shutdown.
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To: qemu-devel@nongnu.org

On Wed, Aug 13, 2008 at 09:40:34PM +0300, Avi Kivity wrote:
> Gleb Natapov wrote:
>> but what bother me is that we
>> consciously drop user data that we can easily save. Why? Real HW tries
>> hard to save every bit of user data and we just decided to drop it. The
>> difference between cancel or complete a request may be corrupted or not
>> corrupted file system after a crash.
>>
>>   
>
> If a guest didn't wait for an I/O to complete, it shouldn't expect it to  
> be on disk.
If you'll save your swiss bank account details in file and suddenly
your guest will crash, you'll surely appreciate if qemu will save it
for you :)

>
> Of course, we can have the IDE layer wait instead of cancelling, which  
> will get the request onto the disk.
>
That is the current approach, but the wait is done for all block IO not
just IDE.

--
			Gleb.