[PATCH 1/2] nvme: add 'fail_if_no_path' sysfs attribute

[Hannes Reinecke]

On 2/24/21 11:47 PM, Sagi Grimberg wrote:
> 
> 
> On 2/23/21 3:59 AM, Hannes Reinecke wrote:
>> In some setups like RAID or cluster we need to return an I/O error
>> once all paths are unavailable to allow the upper layers to start
>> their own error recovery (like redirecting I/O to other mirrors).
>> This patch adds a sysfs attribute 'fail_if_no_path' to allow the
>> admin to enable that behaviour instead of the current 'queue until
>> a path becomes available' policy.
> 
> Doesn't the same happen today if all the controllers are set with
> fail_io_fast_tmo=0? nvme_available_path will return false if all
> the paths have NVME_CTRL_FAILFAST_EXPIRED set.
> 
> I think that fail_io_fast_tmo should be settable via sysfs and I
> think I requested that during the various submission iterations...
> 
> I'm not sure this should be controlled on the individual namespace level...

Indeed, you are right; using 'fast_io_fail_tmo' works as well here.
So I'll be redoing the patch series and will be replacing this patch 
with another one adding a per-controller 'fast_io_fail_tmo' sysfs attribute.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
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