Re: [PATCH] efivarfs: Cache occupied and available space

On Sat, 1 Aug 2026, at 17:42, Ard Biesheuvel wrote:
> Ravi reports that statfs() may be called by unprivileged users on the
> efivarfs mount point, resulting in repeated calls to QueryVariableInfo()
> which are disproportionately costly on x86 systems where the variable
> store is backed by SMM, as each SMM entry requires a rendez-vous of all
> the CPUs.
>
> So cache the output of QueryVariableInfo(), and invalidate the cached
> values when an entry is added or deleted, or the variable store is
> synchronized after a suspend/resume sequence.
>
> Cc: <[email protected]>
> Reported-by: Ravi Bangoria <[email protected]>
> Fixes: d86ff3333cb1 ("efivarfs: expose used and total size")
> Signed-off-by: Ard Biesheuvel <[email protected]>
> ---
>  fs/efivarfs/internal.h |  2 ++
>  fs/efivarfs/super.c    | 21 +++++++++++---------
>  fs/efivarfs/vars.c     |  9 +++++++++
>  3 files changed, 23 insertions(+), 9 deletions(-)
>

Applied to efi/next