Re: [PATCH v2] nvme: check at least one ns identification reported

[Guixin Liu <kanie@linux.alibaba.com>]

在 2024/11/7 13:28, Christoph Hellwig 写道:
> On Wed, Nov 06, 2024 at 06:47:43PM +0800, Guixin Liu wrote:
>> I assume that the dm-multipath
> dm-multipath is not supported with nvme..

Dm-multipath can be configured to support nvme,

/etc/multipath.conf:

     devices {
         device {
                 vendor "NVME"
                 product ".*"
                 path_grouping_policy group_by_prio
         }
     }

Here is the result of "multipath -l":

uuid.a2c24be7-ed8e-4033-9f26-5b9f230265fb dm-0NVME,Linux
size=1.0G features='0' hwhandler='0' wp=rw
`-+- policy='service-time 0' prio=0 status=active
   |- 0:1:2:1 nvme0n2 259:0 active undef running
   `- 1:2:2:1 nvme1n2 259:3 active undef running


If the target haven't report any indentification, the dm-multipath

will use wwid which generated by nvme host driver to recognize

which namespaces should be merged.

Here is the result of "multipath -l", if we dont report any identification:

nvme.0000-6135363837366563633830646133663261643034-4c696e7578-00000001 
dm-0 NVME,Linux
size=1.0G features='0' hwhandler='0' wp=rw
`-+- policy='service-time 0' prio=0 status=active
   |- 0:1:1:1 nvme0n1 259:0 active undef running
   `- 1:2:1:1 nvme1n1 259:3 active undef running

>> will not recognize nvme device if nothing to
>> return,
> But more importantly the user of the sysfs files is the right place
> the just check for these values being non-present.  As said before
> it's perfectly valid for 1.0 devices so they have to cope with it
> anyway.  I don't think a message in the kernel log that is very to
> process algorithmically is not very useful.
>
> (I really with we'd have useful and required identifiers from the
> start, but that's a separate discussion)

Agree, I just worry about that some components denpend on this, currently,

no problem.

Best Regards,

Guixin Liu