On 18.01.20 20:09, Alberto Garcia wrote:
> When updating an L1 entry the qcow2 driver writes a (512-byte) sector
> worth of data to avoid a read-modify-write cycle. Instead of always
> writing 512 bytes we should follow the alignment requirements of the
> storage backend.
> 
> (the only exception is when the alignment is larger than the cluster
> size because then we could be overwriting data after the L1 table)
> 
> Signed-off-by: Alberto Garcia <berto@igalia.com>
> ---
>  block/qcow2-cluster.c | 25 +++++++++++++++----------
>  1 file changed, 15 insertions(+), 10 deletions(-)

Reviewed-by: Max Reitz <mreitz@redhat.com>