[PATCH] nvme-multipath: expose path_state via sysfs

[Guixin Liu]

>
> Instead of only exposing disabled/enabled state, can we also expose the
> reason why the path was not usable?
>
> For instance, path_state attribute shall expose "enabled" when it's
> available for I/O (this is straightforward):
> - enabled
>
> But in case path is not usable/available then expose "disabled" along
> with the reason:
> - disabled (ctrl_down)
> - disabled (ana_pending)
> - disabled (ns_not_ready)
>
> Or any other combination depending on the ns->flags and ctrl->state.
>
> That way, the userspace would know the exact reason when path is
> not available/usable for I/O.
>
> Thanks,
> --Nilay
Good idea, I will add this in v2, thanks.

Best Regards,
Guixin Liu