Re: [PATCH v9 3/7] block: add block layer APIs resembling Linux ZonedBlockDevice ioctls

[Sam Li]

Klaus Jensen <its@irrelevant.dk> 于2022年9月20日周二 16:51写道：
>
> On Sep 10 13:27, Sam Li wrote:
> > Add a new zoned_host_device BlockDriver. The zoned_host_device option
> > accepts only zoned host block devices. By adding zone management
> > operations in this new BlockDriver, users can use the new block
> > layer APIs including Report Zone and four zone management operations
> > (open, close, finish, reset).
> >
> > Qemu-io uses the new APIs to perform zoned storage commands of the device:
> > zone_report(zrp), zone_open(zo), zone_close(zc), zone_reset(zrs),
> > zone_finish(zf).
> >
> > For example, to test zone_report, use following command:
> > $ ./build/qemu-io --image-opts -n driver=zoned_host_device, 
> > filename=/dev/nullb0
> > -c "zrp offset nr_zones"
> >
> > Signed-off-by: Sam Li <faithilikerun@gmail.com>
> > Reviewed-by: Hannes Reinecke <hare@suse.de>
> > ---
> >  block/block-backend.c             | 145 ++++++++++++++
> >  block/file-posix.c                | 323 +++++++++++++++++++++++++++++-
> >  block/io.c                        |  41 ++++
> >  include/block/block-io.h          |   7 +
> >  include/block/block_int-common.h  |  21 ++
> >  include/block/raw-aio.h           |   6 +-
> >  include/sysemu/block-backend-io.h |  17 ++
> >  meson.build                       |   1 +
> >  qapi/block-core.json              |   8 +-
> >  qemu-io-cmds.c                    | 143 +++++++++++++
> >  10 files changed, 708 insertions(+), 4 deletions(-)
> >
> > +/*
> > + * zone management operations - Execute an operation on a zone
> > + */
> > +static int coroutine_fn raw_co_zone_mgmt(BlockDriverState *bs, BlockZoneOp 
> > op,
> > +        int64_t offset, int64_t len) {
> > +#if defined(CONFIG_BLKZONED)
> > +    BDRVRawState *s = bs->opaque;
> > +    RawPosixAIOData acb;
> > +    int64_t zone_sector, zone_sector_mask;
> > +    const char *zone_op_name;
> > +    unsigned long zone_op;
> > +    bool is_all = false;
> > +
> > +    zone_sector = bs->bl.zone_sectors;
> > +    zone_sector_mask = zone_sector - 1;
> > +    if (offset & zone_sector_mask) {
> > +        error_report("sector offset %" PRId64 " is not aligned to zone 
> > size "
> > +                     "%" PRId64 "", offset, zone_sector);
> > +        return -EINVAL;
> > +    }
> > +
> > +    if (len & zone_sector_mask) {
> > +        error_report("number of sectors %" PRId64 " is not aligned to zone 
> > size"
> > +                      " %" PRId64 "", len, zone_sector);
> > +        return -EINVAL;
> > +    }
>
> These checks impose a power-of-two constraint on the zone size. Can they
> be changed to divisions to lift that constraint? I don't see anything in
> this patch set that relies on power of two zone sizes.

Yes, it can be changed when the kernel block layer has non-power-of-2
zone sizes support. For now, Dmitry's work on zoned device support on
the kernel side put the constraint on zone sectors to be po2. The
checks here follow this constraint.

Dmitry's patches can be found here:
https://lore.kernel.org/linux-block/20220919022921.946344-1-dmitry.fomichev@wdc.com/T/#m9b0b3c8220de1307e53235d1a73dab1e3a10f62b


Sam