On 01.06.15 18:09, Max Reitz wrote: > The L2 cache must cover at least two L2 tables, because during COW two > L2 tables are accessed simultaneously. > > Reported-by: Alexander Graf <ag...@suse.de> > Cc: qemu-stable <qemu-sta...@nongnu.org> > Signed-off-by: Max Reitz <mre...@redhat.com>
Tested-by: Alexander Graf <ag...@suse.de> Alex > --- > block/qcow2.h | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/block/qcow2.h b/block/qcow2.h > index 0076512..aa20022 100644 > --- a/block/qcow2.h > +++ b/block/qcow2.h > @@ -62,7 +62,8 @@ > #define MIN_CLUSTER_BITS 9 > #define MAX_CLUSTER_BITS 21 > > -#define MIN_L2_CACHE_SIZE 1 /* cluster */ > +/* Must be at least 2 to cover COW */ > +#define MIN_L2_CACHE_SIZE 2 /* clusters */ > > /* Must be at least 4 to cover all cases of refcount table growth */ > #define MIN_REFCOUNT_CACHE_SIZE 4 /* clusters */ >
