Re: [PATCH v3] null_blk: add support for max open/active zone limit for zoned devices

[Johannes Thumshirn]

On 17/09/2020 09:57, Niklas Cassel wrote:
> On Mon, Sep 07, 2020 at 08:18:26AM +0000, Niklas Cassel wrote:
>> On Fri, Aug 28, 2020 at 12:54:00PM +0200, Niklas Cassel wrote:
>>> Add support for user space to set a max open zone and a max active zone
>>> limit via configfs. By default, the default values are 0 == no limit.
>>>
>>> Call the block layer API functions used for exposing the configured
>>> limits to sysfs.
>>>
>>> Add accounting in null_blk_zoned so that these new limits are respected.
>>> Performing an operation that would exceed these limits results in a
>>> standard I/O error.
>>>
>>> A max open zone limit exists in the ZBC standard.
>>> While null_blk_zoned is used to test the Zoned Block Device model in
>>> Linux, when it comes to differences between ZBC and ZNS, null_blk_zoned
>>> mostly follows ZBC.
>>>
>>> Therefore, implement the manage open zone resources function from ZBC,
>>> but additionally add support for max active zones.
>>> This enables user space not only to test against a device with an open
>>> zone limit, but also to test against a device with an active zone limit.
>>>
>>> Signed-off-by: Niklas Cassel <niklas.cassel@xxxxxxx>
>>> Reviewed-by: Damien Le Moal <damien.lemoal@xxxxxxx>
>>> ---
>>> Changes since v2:
>>> -Picked up Damien's Reviewed-by tag.
>>> -Fixed a typo in the commit message.
>>> -Renamed null_manage_zone_resources() to null_has_zone_resources().
>>>
>>>  drivers/block/null_blk.h       |   5 +
>>>  drivers/block/null_blk_main.c  |  16 +-
>>>  drivers/block/null_blk_zoned.c | 319 +++++++++++++++++++++++++++------
>>>  3 files changed, 282 insertions(+), 58 deletions(-)
>>
>> Hello Jens,
>>
>> A gentle ping on this.
>>
>> As far as I can tell, there are no outstanding review comments.
> 
> 
> Hello Jens,
> 
> Pinging you from another address, in case my corporate email is getting
> stuck in your spam filter.
> 
> Kind regards,
> Niklas
> 


Jens,

Any chance we can get this queued up for 5.10? This is really helpful for e.g. 
the zonefs test suite or xfstests when btrfs HMZONED support lands.

Thanks,
	Johannes