[PATCH] nvme: add namespace paths links

[Hannes Reinecke]

On 4/5/22 10:34, Sagi Grimberg wrote:
> 
>>>>> It is really annoying to always have to loop through the entire
>>>>> /sys/block directory just to find the namespace path links for
>>>>> a single namespace in libnvme/nvme-cli.
>>>>> So provide links to the namespace paths for efficient lookup.
>>>>
>>>> I think having some form of links would be useful.  Quite a while ago
>>>> Thadeu looked into adding some form of relationship for lsblk and
>>>> friends.  Maybe it would be good to sync up and make sure whatever
>>>> links we are adding would be useful for all users?
>>>>
>>> Care to elaborate?
>>> Using the block device name is the most straightforward way here; we 
>>> don't
>>> have a good enumeration to leverage as the paths are essentially just a
>>> linked list.
>>>
>>> We sure can have a subdirectory 'paths', and stick the links in there.
>>> If that helps with lsblk ...
>>
>> I personally don't care.  But I've added Thadeu and the util-linux list
>> to get everyone on board.
> 
> Why not stick to slaves/ like the device mapper?

Because:

/**
  * bd_link_disk_holder - create symlinks between holding disk and slave 
bdev
  * @bdev: the claimed slave bdev
  * @disk: the holding disk
  *
  * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
  *

Not sure _why_ it's there, but it is there.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		           Kernel Storage Architect
hare at suse.de			                  +49 911 74053 688
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