Based-on: https://lore.kernel.org/qemu-devel/20240429115157.2260885-1-vsement...@yandex-team.ru/
Discussion for v1: https://lore.kernel.org/qemu-devel/20240308155158.830258-1-f.eb...@proxmox.com/ Changes in v2: * Use 'size' type in QAPI. * Remove option in cbw_parse_options(), i.e. before parsing generic blockdev options. * Reword commit messages hoping to describe the issue in a more straight-forward way. In the context of backup fleecing, discarding the source will not work when the fleecing image has a larger granularity than the one used for block-copy operations (can happen if the backup target has smaller cluster size), because cbw_co_pdiscard_snapshot() will align down the discard requests and thus effectively ignore then. To make @discard-source work in such a scenario, allow specifying the minimum cluster size used for block-copy operations and thus in particular also the granularity for discard requests to the source. Fiona Ebner (2): copy-before-write: allow specifying minimum cluster size backup: add minimum cluster size to performance options block/backup.c | 2 +- block/block-copy.c | 22 ++++++++++++++++++---- block/copy-before-write.c | 18 +++++++++++++++++- block/copy-before-write.h | 1 + blockdev.c | 3 +++ include/block/block-copy.h | 1 + qapi/block-core.json | 17 ++++++++++++++--- 7 files changed, 55 insertions(+), 9 deletions(-) -- 2.39.2
