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

[Hannes Reinecke]

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.
> 
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
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