Re: [Qemu-devel] [PATCH] qcow2: Fix refcount block allocation during qcow2_allocate_cluster_at()

[Marcelo Tosatti]

On Mon, Apr 23, 2012 at 02:33:49PM +0200, Kevin Wolf wrote:
> Am 23.04.2012 01:35, schrieb Marcelo Tosatti:
> > On Sun, Apr 22, 2012 at 08:18:49PM -0300, Marcelo Tosatti wrote:
> >> On Fri, Apr 20, 2012 at 03:56:01PM +0200, Kevin Wolf wrote:
> >>> Refcount block allocation and refcount table growth rely on
> >>> s->free_cluster_index pointing to somewhere after the current
> >>> allocation. Change qcow2_allocate_cluster_at() to fulfill this
> >>> assumption.
> >>>
> >>> Without this change it could happen that a newly allocated refcount
> >>> block and the allocated data block point to the same area in the image
> >>> file, causing data corruption in the long run.
> >>>
> >>> This fixes a bug that became first visible after commit 250196f1.
> >>>
> >>> Signed-off-by: Kevin Wolf <address@hidden>
> >>
> >> Kevin,
> >>
> >> This patch fixes explicit filesystem errors (qemu-img check also OK), 
> >> but autotest is still failing, see attached screenshot. It is not
> >> reproducible without
> >>
> >> f081987ad20a8c8dc391deded55161ea8d38be5f
> > 
> > Sorry, i meant
> > 
> > commit 250196f19c6e7df12965d74a5073e10aba06c802
> > Author: Kevin Wolf <address@hidden>
> > Date:   Fri Mar 2 14:10:54 2012 +0100
> > 
> >     qcow2: Reduce number of I/O requests
> 
> The screenshot doesn't really give a lot of information, but let's
> assume that _something_ must have been corrupted... Can you try finding
> the corrupted file (e.g. using rpm -V) and see in which way it differs
> from the real one?
> 
> Kevin

Unfortunately no, /boot/vmlinuz is gone on the last install
(screenshot).

It should be easy to reproduce, install Fedora.8.64, or i
can upload an image later tonight if that is helpful.

fc8-64-corrupted.png
Description: PNG image