Re: [PATCH v8 0/7] Add support for zoned device

[Sam Li]

Stefan Hajnoczi <stefanha@redhat.com> 于2022年8月30日周二 03:44写道：
>
> On Fri, Aug 26, 2022 at 11:15:29PM +0800, Sam Li wrote:
> > Zoned Block Devices (ZBDs) devide the LBA space to block regions called 
> > zones
> > that are larger than the LBA size. It can only allow sequential writes, 
> > which
> > reduces write amplification in SSD, leading to higher throughput and 
> > increased
> > capacity. More details about ZBDs can be found at:
> >
> > https://zonedstorage.io/docs/introduction/zoned-storage
> >
> > The zoned device support aims to let guests (virtual machines) access zoned
> > storage devices on the host (hypervisor) through a virtio-blk device. This
> > involves extending QEMU's block layer and virtio-blk emulation code.  In its
> > current status, the virtio-blk device is not aware of ZBDs but the guest 
> > sees
> > host-managed drives as regular drive that will runs correctly under the most
> > common write workloads.
> >
> > This patch series extend the block layer APIs with the minimum set of zoned
> > commands that are necessary to support zoned devices. The commands are - 
> > Report
> > Zones, four zone operations and Zone Append (developing).
> >
> > It can be tested on a null_blk device using qemu-io or qemu-iotests. For
> > example, the command line for zone report using qemu-io is:
> > $ path/to/qemu-io --image-opts -n 
> > driver=zoned_host_device,filename=/dev/nullb0
> > -c "zrp offset nr_zones"
> >
> > v8:
> > - address review comments
> >   * solve patch conflicts and merge sysfs helper funcations into one patch
> >   * add cache.direct=on check in config
>
> Hi Sam,
> I have left a few comments.

That's great! Thanks for reviewing. I'll send a revision soon.

Sam