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

[Sebastian Andrzej Siewior]

On 2026-09-24 18:45:28 [-0700], Prashant Singh wrote:
> 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.

Having -o remount,statfs=on and remount,statfs=off working would
probably improve the situation.

> I'll send v3 with that change shortly.
> 
> Thanks,
> Prashant

Sebastian