On Sat, Dec 14, 2013 at 01:29:28AM +0800, Liu Yuan wrote: > When running qcow2 over sheepdog, we might meet following problem > > qemu-system-x86_64: shrinking is not supported > > And cause IO errors to Guest. This is because we abuse bs->total_sectors, > which > is manipulated by generic block layer and race with sheepdog code. > > We should directly check if offset > vdi_size to dynamically enlarge the > volume > instead of 'offset > bs->total_sectors', which will cause problem when > following > case happens: > > vdi_size > offset > bs->total_sectors > > # then trigger sd_truncate() to shrink the volume wrongly. > > Cc: qemu-devel@nongnu.org > Cc: Kevin Wolf <kw...@redhat.com> > Cc: Stefan Hajnoczi <stefa...@redhat.com> > Reported-by: Hadrien KOHL <hadrien.k...@gmail.com> > Signed-off-by: Liu Yuan <namei.u...@gmail.com> > --- > block/sheepdog.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-)
block.c already updates bs->total_sectors if bs->growable so this patch is safe. Thanks, applied to my block tree: https://github.com/stefanha/qemu/commits/block Stefan
