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 In some cases the test reference output may be outdated and you can simply copy the 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, Stefan
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