Subject: Re: Corrupt data when reading filesystems under Linux guest
To: Thor Lancelot Simon <tls@rek.tjls.com>
From: Manuel Bouyer <bouyer@antioche.eu.org>
List: port-xen
Date: 06/14/2005 19:54:11
On Tue, Jun 14, 2005 at 11:42:24AM -0400, Thor Lancelot Simon wrote:
> On Tue, Jun 14, 2005 at 03:32:42PM +0200, Manuel Bouyer wrote:
> >
> > I think we can deal with this by sending a partial xfer to the drive, it
> > shouldn't break anything. But obviously the completion message has to be
> > sent only one the whole request has been handled.
>
> What if the domain 0 kernel crashes, or the system is powered down,
> between the partial transfer and the remaining part? Now neither the
> old nor the new data is actually intact on disk. This could have a
> rather negative impact on, for example, filesystem metadata...
Isn't it something that can already happen inside the disk ? It's not clear if
multi-sector writes are atomics.
--
Manuel Bouyer <bouyer@antioche.eu.org>
NetBSD: 26 ans d'experience feront toujours la difference
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