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From: Jamie Lokier <jamie@shareable.org>
To: Kevin Wolf <kwolf@suse.de>
Cc: qemu-devel@nongnu.org, kvm-devel <kvm@vger.kernel.org>,
	Laurent Vivier <laurent@lvivier.info>
Subject: Re: [Qemu-devel] qcow2 corruption observed,	fixed by reverting old change
Date: Wed, 11 Feb 2009 16:48:14 +0000	[thread overview]
Message-ID: <20090211164814.GA7161@shareable.org> (raw)
In-Reply-To: <4992C77D.4030104@suse.de>

Kevin Wolf wrote:
> Besides reviewing the code over and over again, I think the only real
> chance is that you can get a non-productive copy of your image and add
> some debug code so that we can see at least which code path is causing
> problems.

I have a copy of my image to reproduce the bug, so I can test patches
including diagnostic patches.  That's what I did to narrow it down.

Being a company mail server, I can't send you the image of course.

> > Aside from logic, the code mixes signed 32-bit with unsigned 64-bit
> > with unclear naming which would make me nervous.  My host is 64-bit,
> > by the way.
> 
> I would suspect that simply having a 64 bit host isn't enough to trigger
> the problem. These patches were in for half a year now without anyone
> noticing such failure.

It was just for clarity.  If there are any bugs it's more likely to be
truncation on a 32 bit host :-)

I didn't see any mention of "long", so the code should behave the
same on 64-bit and 32-bit hosts.

> By the way and completely off-topic: Have you already tried to use the
> VHD patches? I would really like to know if they fix your problems.

Are those patches in kvm-83?  I still have the image that was causing
problems way back, and I'm converting it to raw now with kvm-83 to see
if it now matches the raw image produced by VPC's own tool.

Beyond checking that it reads ok, which it didn't before, I don't know
how to test the VPC support properly, but I can try booting the image
and see if it at least doesn't fsck^H^H^H^Hscandisk like it used to.

I'm not using VPC images any more, we just install Windows into empty
QCOW2 or raw images, like everyone else. :-)

At some point I may test the VPC support with prebuilt images
downloaded from Microsoft - you can too!

-- Jamie

WARNING: multiple messages have this Message-ID
From: Jamie Lokier <jamie@shareable.org>
To: Kevin Wolf <kwolf@suse.de>
Cc: Laurent Vivier <laurent@lvivier.info>,
	qemu-devel@nongnu.org, kvm-devel <kvm@vger.kernel.org>
Subject: Re: [Qemu-devel] qcow2 corruption observed, fixed by reverting old change
Date: Wed, 11 Feb 2009 16:48:14 +0000	[thread overview]
Message-ID: <20090211164814.GA7161@shareable.org> (raw)
In-Reply-To: <4992C77D.4030104@suse.de>

Kevin Wolf wrote:
> Besides reviewing the code over and over again, I think the only real
> chance is that you can get a non-productive copy of your image and add
> some debug code so that we can see at least which code path is causing
> problems.

I have a copy of my image to reproduce the bug, so I can test patches
including diagnostic patches.  That's what I did to narrow it down.

Being a company mail server, I can't send you the image of course.

> > Aside from logic, the code mixes signed 32-bit with unsigned 64-bit
> > with unclear naming which would make me nervous.  My host is 64-bit,
> > by the way.
> 
> I would suspect that simply having a 64 bit host isn't enough to trigger
> the problem. These patches were in for half a year now without anyone
> noticing such failure.

It was just for clarity.  If there are any bugs it's more likely to be
truncation on a 32 bit host :-)

I didn't see any mention of "long", so the code should behave the
same on 64-bit and 32-bit hosts.

> By the way and completely off-topic: Have you already tried to use the
> VHD patches? I would really like to know if they fix your problems.

Are those patches in kvm-83?  I still have the image that was causing
problems way back, and I'm converting it to raw now with kvm-83 to see
if it now matches the raw image produced by VPC's own tool.

Beyond checking that it reads ok, which it didn't before, I don't know
how to test the VPC support properly, but I can try booting the image
and see if it at least doesn't fsck^H^H^H^Hscandisk like it used to.

I'm not using VPC images any more, we just install Windows into empty
QCOW2 or raw images, like everyone else. :-)

At some point I may test the VPC support with prebuilt images
downloaded from Microsoft - you can too!

-- Jamie

  reply	other threads:[~2009-02-11 16:48 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-02-11  7:00 Jamie Lokier
2009-02-11  7:00 ` [Qemu-devel] " Jamie Lokier
2009-02-11  9:57 ` Kevin Wolf
2009-02-11 11:27   ` Jamie Lokier
2009-02-11 11:27     ` Jamie Lokier
2009-02-11 11:41   ` Jamie Lokier
2009-02-11 11:41     ` Jamie Lokier
2009-02-11 12:41     ` Kevin Wolf
2009-02-11 12:41       ` Kevin Wolf
2009-02-11 16:48       ` Jamie Lokier [this message]
2009-02-11 16:48         ` Jamie Lokier
2009-02-12 22:57         ` Consul
2009-02-12 22:57           ` [Qemu-devel] " Consul
2009-02-12 23:19           ` Consul
2009-02-12 23:19             ` [Qemu-devel] " Consul
2009-02-13  7:50             ` Marc Bevand
2009-02-16 12:44         ` [Qemu-devel] " Kevin Wolf
2009-02-17  0:43           ` Jamie Lokier
2009-02-17  0:43             ` Jamie Lokier
2009-03-06 22:37         ` Filip Navara
2009-03-06 22:37           ` Filip Navara
2009-02-12  5:45       ` Chris Wright
2009-02-12  5:45         ` Chris Wright
2009-02-12 11:08         ` Johannes Schindelin
2009-02-12 11:08           ` Johannes Schindelin
2009-02-13  6:41 ` Marc Bevand
2009-02-13 11:16   ` Kevin Wolf
2009-02-13 11:16     ` [Qemu-devel] " Kevin Wolf
2009-02-13 16:23     ` Jamie Lokier
2009-02-13 16:23       ` Jamie Lokier
2009-02-13 18:43       ` Chris Wright
2009-02-13 18:43         ` Chris Wright
2009-02-14  6:31       ` Marc Bevand
2009-02-14 22:28         ` Dor Laor
2009-02-14 22:28           ` Dor Laor
2009-02-15  2:27           ` Jamie Lokier
2009-02-15  7:56           ` Marc Bevand
2009-02-15  7:56             ` Marc Bevand
2009-02-15  2:37         ` Jamie Lokier
2009-02-15 10:57     ` Gleb Natapov
2009-02-15 10:57       ` [Qemu-devel] " Gleb Natapov
2009-02-15 11:46       ` Marc Bevand
2009-02-15 11:46         ` [Qemu-devel] " Marc Bevand
2009-02-15 11:54         ` Marc Bevand
2009-02-15 11:54           ` [Qemu-devel] " Marc Bevand

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