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

[Mario Limonciello <superm1@kernel.org>]

On 7/13/26 11:58 PM, Greg KH wrote:
> 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?

Oh I mentioned it above between Ard's S-o-b and mine:

d86ff3333cb1 ("efivarfs: expose used and total size")