On Sun, 10 Sept 2023 at 06:53, Heinrich Schuchardt
<heinrich.schuchardt@xxxxxxxxxxxxx> wrote:
>
> Some firmware (notably U-Boot) provides GetVariable() and
> GetNextVariableName() but not QueryVariableInfo().
>
> With commit d86ff3333cb1 ("efivarfs: expose used and total size") the
> statfs syscall was broken for such firmware.
>
> If QueryVariableInfo() does not exist or returns an error, just report the
> file-system size as 0 as statfs_simple() previously did.
>
> Fixes: d86ff3333cb1 ("efivarfs: expose used and total size")
> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@xxxxxxxxxxxxx>
> ---
> v2:
> initialize remaining_space to 0
Thanks for the patch, and apologies for the oversight.
> ---
> fs/efivarfs/super.c | 20 ++++++++++++--------
> 1 file changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/fs/efivarfs/super.c b/fs/efivarfs/super.c
> index e028fafa04f3..3893aae6a9be 100644
> --- a/fs/efivarfs/super.c
> +++ b/fs/efivarfs/super.c
> @@ -29,14 +29,9 @@ static int efivarfs_statfs(struct dentry *dentry, struct kstatfs *buf)
> const u32 attr = EFI_VARIABLE_NON_VOLATILE |
> EFI_VARIABLE_BOOTSERVICE_ACCESS |
> EFI_VARIABLE_RUNTIME_ACCESS;
> - u64 storage_space, remaining_space, max_variable_size;
> + u64 storage_space, remaining_space = 0, max_variable_size;
Shouldn't storage_space be set to 0 too?
> efi_status_t status;
>
> - status = efivar_query_variable_info(attr, &storage_space, &remaining_space,
> - &max_variable_size);
> - if (status != EFI_SUCCESS)
> - return efi_status_to_err(status);
> -
> /*
> * This is not a normal filesystem, so no point in pretending it has a block
> * size; we declare f_bsize to 1, so that we can then report the exact value
> @@ -44,10 +39,19 @@ static int efivarfs_statfs(struct dentry *dentry, struct kstatfs *buf)
> */
> buf->f_bsize = 1;
> buf->f_namelen = NAME_MAX;
> - buf->f_blocks = storage_space;
> - buf->f_bfree = remaining_space;
> buf->f_type = dentry->d_sb->s_magic;
>
> + /* Some UEFI firmware does not implement QueryVariable() */
> + if (efi_rt_services_supported(EFI_RT_SUPPORTED_QUERY_VARIABLE_INFO)) {
> + status = efivar_query_variable_info(attr, &storage_space,
> + &remaining_space,
> + &max_variable_size);
> + if (status == EFI_SUCCESS) {
> + buf->f_blocks = storage_space;
> + buf->f_bfree = remaining_space;
> + }
> + }
> +
I'd prefer not to ignore the error completely here. How about we do
--- a/fs/efivarfs/super.c
+++ b/fs/efivarfs/super.c
@@ -32,10 +32,15 @@ static int efivarfs_statfs(struct dentry *dentry,
struct kstatfs *buf)
u64 storage_space, remaining_space, max_variable_size;
efi_status_t status;
- status = efivar_query_variable_info(attr, &storage_space,
&remaining_space,
- &max_variable_size);
- if (status != EFI_SUCCESS)
- return efi_status_to_err(status);
+ /* Some UEFI firmware does not implement QueryVariableInfo() */
+ storage_space = remaining_space = 0;
+ if (efi_rt_services_supported(EFI_RT_SUPPORTED_QUERY_VARIABLE_INFO)) {
+ status = efivar_query_variable_info(attr, &storage_space,
+ &remaining_space,
+ &max_variable_size);
+ if (status != EFI_SUCCESS && status != EFI_UNSUPPORTED)
+ return efi_status_to_err(status);
+ }
/*
* This is not a normal filesystem, so no point in pretending
it has a block
(no need to resend if you agree)
