[dm-devel] [PATCHv3 00/11] dm-zoned: metadata version 2

[Bob Liu]

On 4/14/20 11:13 PM, Mike Snitzer wrote:
> On Tue, Apr 14 2020 at  2:38am -0400,
> Hannes Reinecke <hare at suse.de> wrote:
> 
>> On 4/11/20 2:30 PM, Bob Liu wrote:
>>> On 4/9/20 2:45 PM, Hannes Reinecke wrote:
>>>> Hi all,
>>>>
>>>> this patchset adds a new metadata version 2, which brings the following
>>>> improvements:
>>>> - UUIDs and labels: Adding three more fields to the metadata containing
>>>>   the dm-zoned device UUID and label, and the device UUID. This allows
>>>>   for an unique identification of the devices, so that several dm-zoned
>>>>   sets can coexist and have a persistent identification.
>>>> - Extend random zones by an additional regular disk device: A regular
>>>>   block device can be added together with the zoned block device, providing
>>>>   additional (emulated) random write zones. With this it's possible to
>>>>   handle sequential zones only devices; also there will be a speed-up if
>>>>   the regular block device resides on a fast medium. The regular block device
>>>>   is placed logically in front of the zoned block device, so that metadata
>>>>   and mapping tables reside on the regular block device, not the zoned device.
>>>> - Tertiary superblock support: In addition to the two existing sets of metadata
>>>>   another, tertiary, superblock is written to the first block of the zoned
>>>>   block device. This superblock is for identification only; the generation
>>>>   number is set to '0' and the block itself it never updated. The additional
>>>>   metadate like bitmap tables etc are not copied.
>>>>
>>>> To handle this, some changes to the original handling are introduced:
>>>> - Zones are now equidistant. Originally, runt zones were ignored, and
>>>>   not counted when sizing the mapping tables. With the dual device setup
>>>>   runt zones might occur at the end of the regular block device, making
>>>>   direct translation between zone number and sector/block number complex.
>>>>   For metadata version 2 all zones are considered to be of the same size,
>>>>   and runt zones are simply marked as 'offline' to have them ignored when
>>>>   allocating a new zone.
>>>> - The block number in the superblock is now the global number, and refers to
>>>>   the location of the superblock relative to the resulting device-mapper
>>>>   device. Which means that the tertiary superblock contains absolute block
>>>>   addresses, which needs to be translated to the relative device addresses
>>>>   to find the referenced block.
>>>>
>>>> There is an accompanying patchset for dm-zoned-tools for writing and checking
>>>> this new metadata.
>>>>
>>>> As usual, comments and reviews are welcome.
>>>>
>>>> Changes to v2:
>>>> - Kill dmz_id()
>>>> - Include reviews from Damien
>>>> - Sanitize uuid handling as suggested by John Dorminy
>>>>
>>>
>>> This series looks good to me, feel free to add my
>>> Reviewed-by: Bob Liu <bob.liu at oracle.com>
>>>
>>> By the way, have you completed the patches for regular device support?
>>> I was considering rebase my previous patches to this series but not sure is it still necessary.
> 
> Bob, not trying to be overly critical but if you couldn't answer your

These patches did looks fine to me, my question was asking about following regular-device support
patches which haven't included in this series.
Anyway, I will pay more attention.
Thanks for reminding.

Bob

> question how did you feel comfortable providing your Reviewed-by to this
> patchset?  That Reviewed-by _must_ mean something.
> 
> Mike
> 
> 
>> I have combined both patchsets, this one now also included regular
>> device support. So no need to resend from your side.
>>
>> Cheers,
>>
>> Hannes
>> -- 
>> Dr. Hannes Reinecke            Teamlead Storage & Networking
>> hare at suse.de                               +49 911 74053 688
>> SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
>> HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer
>>
>