On 6/10/20 4:46 AM, Alberto Garcia wrote:
When resizing an image with qcow2_co_truncate() using the falloc or full preallocation modes the code assumes that both the old and new sizes are cluster-aligned.There are two problems with this: 1) The calculation of how many clusters are involved does not always get the right result. Example: creating a 60KB image and resizing it (with preallocation=full) to 80KB won't allocate the second cluster. 2) No copy-on-write is performed, so in the previous example if there is a backing file then the first 60KB of the first cluster won't be filled with data from the backing file. This patch fixes both issues. Signed-off-by: Alberto Garcia <[email protected]> --- block/qcow2.c | 17 ++++++++++++++--- tests/qemu-iotests/125 | 21 +++++++++++++++++++++ tests/qemu-iotests/125.out | 9 +++++++++ 3 files changed, 44 insertions(+), 3 deletions(-)
Reviewed-by: Eric Blake <[email protected]> -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org
