On Tue, Jun 2, 2026 at 10:06 PM Stefan Hajnoczi <[email protected]> wrote: > > On Mon, Jun 01, 2026 at 11:44:00PM +0200, Sam Li wrote: > > This patch series add a new extension - zoned format - to the > > qcow2 driver, allowing full zoned storage emulation on a qcow2 > > image file. A user can attach such an image to a guest and have > > it appear as a host-managed zoned block device. > > > > The zoned format is opt-in through a new qcow2 header extension > > that pins the zone geometry. Behind the extension is a dedicated > > zoned metadata region that stores one 8-byte write pointer (WP) > > per zone. The extension is gated by an incompatible bit, so an > > older qcow2 implementation cannot accidentally open the image. > > > > Each write pointer is routed through the write pointer cache, > > a Qcow2Cache object. The write pointer cache is written to disk > > after the qcow2 metadata is written, thus guaranteeing that > > the write pointer is updated after the corresponding data is > > written. > > > > Zone states are in memory. Read-only and offline states are > > device-internal events, which are not modelled in qcow2 > > emulation for simplicity. The other zone states > > (closed, empty, full) can be inferred from write poiner > > values, presistent across QEMU reboots. The open states are > > kept in memory using open zone lists. > > > > To create a qcow2 file with the zoned format: > > > > qemu-img create -f qcow2 zbc.qcow2 \ > > -o size=768M \ > > -o zone.size=64M \ > > -o zone.capacity=64M \ > > -o zone.conventional_zones=0 \ > > -o zone.max_append_bytes=4096 \ > > -o zone.max_open_zones=6 \ > > -o zone.max_active_zones=8 \ > > -o zone.mode=host-managed > > > > Then attach it to a guest via the QEMU command line: > > -blockdev node-name=drive1,driver=qcow2,\ > > file.driver=file,file.filename=zbc.qcow2 \ > > -device virtio-blk-pci,drive=drive1 \ > > Please run `make check-block-qcow` and ensure the tests pass. In some > cases the test reference output may be outdated and you can simply copy > the <test>.out.bad file over the <test>.out reference file.
Thanks, I will check this. Sam
