Re: [PATCH v2] efivarfs: add nostatfs mount option to skip QueryVariableInfo()

[Prashant Singh <singhpra@juniper.net>]

On Thu, 24 Sep 2026, at 13:59, Ard Biesheuvel wrote:
> On Thu, 24 Sep 2026, at 13:36, Luis Claudio R. Goncalves wrote:
>> In this case, corroborating with Sashiko findings, it is necessary to
>> have a way to override that default in kernels with PREEMPT_RT enabled.
>> To be used where this is required for firmware updates.
>
> Indeed.

Agreed -- and thanks Luis and Steve for catching the fwupd impact.

For v3 I'll make the option a negatable flag: "nostatfs" skips
QueryVariableInfo() (and remains the default on PREEMPT_RT), while
"statfs" forces reporting back on. So on an RT kernel, mounting efivarfs
with -o statfs restores the free-space reporting that fwupd needs for
KEK/DB/DBX updates, while the default still avoids the preempt-disabled
firmware call.

I'll send v3 with that change shortly.

Thanks,
Prashant