On 8/06/2026 13:03, Jean-Louis Dupond wrote:
In some cases we want to calculate the size an image will be after we commit A
into B.
This for example on block storage, where you need to resize the target storage
before you start the merge.
These commits adds the functionality to do this.
First of all a commit that adds bdrv_open_backing_chain_until. So we can open
an image up to base image B.
And then a modified qcow2_measure that calculates the size of B after A has
been merged into it.
This with taking into account the discard-no-unref setting of the base.
Jean-Louis Dupond (3):
block: add bdrv_open_backing_chain_until
block: support measure for commit
iotests/290: add test case for qemu-img measure
block.c | 65 +++++++++++++++++----
block/mirror.c | 2 +-
block/qcow2.c | 90 +++++++++++++++++++++++++++---
include/block/block-global-state.h | 7 ++-
qemu-img-cmds.hx | 4 +-
qemu-img.c | 37 ++++++++++--
tests/qemu-iotests/178.out.qcow2 | 6 +-
tests/qemu-iotests/178.out.raw | 6 +-
tests/qemu-iotests/290 | 45 +++++++++++++++
tests/qemu-iotests/290.out | 61 ++++++++++++++++++++
10 files changed, 289 insertions(+), 34 deletions(-)
Kind ping
