Re: [PATCH 6.1.y] efivarfs: expose used and total size

[Greg KH <greg@kroah.com>]

On Mon, Jul 13, 2026 at 11:33:29PM -0500, Mario Limonciello (AMD) wrote:
> From: Anisse Astier <an.astier@criteo.com>
> 
> When writing EFI variables, one might get errors with no other message
> on why it fails. Being able to see how much is used by EFI variables
> helps analyzing such issues.
> 
> Since this is not a conventional filesystem, block size is intentionally
> set to 1 instead of PAGE_SIZE.
> 
> x86 quirks of reserved size are taken into account; so that available
> and free size can be different, further helping debugging space issues.
> 
> With this patch, one can see the remaining space in EFI variable storage
> via efivarfs, like this:
> 
>    $ df -h /sys/firmware/efi/efivars/
>    Filesystem      Size  Used Avail Use% Mounted on
>    efivarfs        176K  106K   66K  62% /sys/firmware/efi/efivars
> 
> Signed-off-by: Anisse Astier <an.astier@criteo.com>
> [ardb: - rename efi_reserved_space() to efivar_reserved_space()
>        - whitespace/coding style tweaks]
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
> (cherry-picked from d86ff3333cb1 ("efivarfs: expose used and total size"))
> Adjusted for headers in linux-6.1.y
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
> ---
> Cc:Steve McIntyre <steve@einval.com> 
> Cc:Richard Hughes <richard@hughsie.com>
> 
> Background for this backport is that fwupd needs to be able to do CA
> updates on Debian oldstable (bookworm) which tracks 6.1.7.  The CA update
> process checks for free storage, and needs this function to do it.

What is the git id of this commit?