Re: [PATCH v7 2/4] qcow2: add configurations for zoned format extension

[Sam Li]

Markus Armbruster <armbru@redhat.com> 于2024年2月19日周一 13:05写道：
>
> One more thing...
>
> Markus Armbruster <armbru@redhat.com> writes:
>
> > I apologize for the delayed review.

No problems. Thanks for reviewing!

> >
> > Sam Li <faithilikerun@gmail.com> writes:
> >
> >> To configure the zoned format feature on the qcow2 driver, it
> >> requires settings as: the device size, zone model, zone size,
> >> zone capacity, number of conventional zones, limits on zone
> >> resources (max append bytes, max open zones, and max_active_zones).
> >>
> >> To create a qcow2 image with zoned format feature, use command like
> >> this:
> >> 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
> >>
> >> Signed-off-by: Sam Li <faithilikerun@gmail.com>
> >
> > [...]
> >
> >> diff --git a/qapi/block-core.json b/qapi/block-core.json
> >> index ca390c5700..e2e0ec21a5 100644
> >> --- a/qapi/block-core.json
> >> +++ b/qapi/block-core.json
> >> @@ -5038,6 +5038,67 @@
> >>  { 'enum': 'Qcow2CompressionType',
> >>    'data': [ 'zlib', { 'name': 'zstd', 'if': 'CONFIG_ZSTD' } ] }
> >>
> >> +##
> >> +# @Qcow2ZoneModel:
> >> +#
> >> +# Zoned device model used in qcow2 image file
> >> +#
> >> +# @host-managed: The host-managed model only allows sequential write over 
> >> the
> >> +#     device zones.
> >> +#
> >> +# Since 8.2
> >> +##
> >> +{ 'enum': 'Qcow2ZoneModel',
> >> +  'data': [ 'host-managed'] }
> >> +
> >> +##
> >> +# @Qcow2ZoneHostManaged:
> >> +#
> >> +# The host-managed zone model.  It only allows sequential writes.
> >> +#
> >> +# @size: Total number of bytes within zones.
> >
> > Default?

It should be set by users. No default value provided. If it's unset
then it is zero and an error will be returned.

> >
> >> +#
> >> +# @capacity: The number of usable logical blocks within zones
> >> +#     in bytes.  A zone capacity is always smaller or equal to the
> >> +#     zone size.
> >
> > Default?

Same.

> >
> >> +# @max-append-bytes: The maximal number of bytes of a zone
> >> +#     append request that can be issued to the device.  It must be
> >> +#     512-byte aligned and less than the zone capacity.
> >
> > Default?

Same.

For those values, I guess it could be set when users provide no
information and still want a workable emulated zoned block device.

> >
> >> +#
> >> +# Since 8.2
> >> +##
> >> +{ 'struct': 'Qcow2ZoneHostManaged',
> >> +  'data': { '*size':          'size',
> >> +            '*capacity':      'size',
> >> +            '*conventional-zones': 'uint32',
> >> +            '*max-open-zones':     'uint32',
> >> +            '*max-active-zones':   'uint32',
> >> +            '*max-append-bytes':   'size' } }
> >> +
> >> +##
> >> +# @Qcow2ZoneCreateOptions:
> >> +#
> >> +# The zone device model for the qcow2 image.
>
> Please document member @mode.
>
> Fails to build since merge commit 61e7a0d27c1:
>
>     qapi/block-core.json: In union 'Qcow2ZoneCreateOptions':
>     qapi/block-core.json:5135: member 'mode' lacks documentation
>

I see. Will update to the latest commit.

> >> +#
> >> +# Since 8.2
> >> +##
> >> +{ 'union': 'Qcow2ZoneCreateOptions',
> >> +  'base': { 'mode': 'Qcow2ZoneModel' },
> >> +  'discriminator': 'mode',
> >> +  'data': { 'host-managed': 'Qcow2ZoneHostManaged' } }
> >> +
> >>  ##
> >>  # @BlockdevCreateOptionsQcow2:
> >>  #
> >> @@ -5080,6 +5141,9 @@
> >>  # @compression-type: The image cluster compression method
> >>  #     (default: zlib, since 5.1)
> >>  #
> >> +# @zone: The zone device model modes.  The default is that the device is
> >> +# not zoned.  (since 8.2)
> >> +#
> >>  # Since: 2.12
> >>  ##
> >>  { 'struct': 'BlockdevCreateOptionsQcow2',
> >> @@ -5096,7 +5160,8 @@
> >>              '*preallocation':   'PreallocMode',
> >>              '*lazy-refcounts':  'bool',
> >>              '*refcount-bits':   'int',
> >> -            '*compression-type':'Qcow2CompressionType' } }
> >> +            '*compression-type':'Qcow2CompressionType',
> >> +            '*zone':            'Qcow2ZoneCreateOptions' } }
> >>
> >>  ##
> >>  # @BlockdevCreateOptionsQed:
>