On Wed, 26 Feb 2025 at 22:48, James Bottomley
<James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Temporarily allow the creation of zero length files in efivarfs so the
> Linux Vendor Firmware Service can continue to operate. This hack should
> be reverted as soon as the LVFS mechanisms for updating firmware have
> been fixed.
>
> LVFS has been coded to open a firmware file, close it, remove the
> immutable bit and write to it. Since commit 908af31f4896 ("efivarfs:
> fix error on write to new variable leaving remnants") this behaviour
> results in the first close removing the file which causes the second
> write to fail. To allow LVFS to keep working code up an indicator of
> size 1 if a write fails and only remove the file on that condition (so
> create at zero size is allowed).
>
> Tested-by: Richard Hughes <richard@xxxxxxxxxxx>
> Signed-off-by: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
> ---
> This should be reverted in the 6.15 release
>
Thanks James. Mind resending this with a MUA that doesn't mangle patches?
> fs/efivarfs/file.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/fs/efivarfs/file.c b/fs/efivarfs/file.c
> index cb1b6d0c3454..c294a8fc566d 100644
> --- a/fs/efivarfs/file.c
> +++ b/fs/efivarfs/file.c
> @@ -57,10 +57,11 @@ static ssize_t efivarfs_file_write(struct file
> *file,
>
> if (bytes == -ENOENT) {
> /*
> - * zero size signals to release that the write deleted
> - * the variable
> + * FIXME: temporary workaround for fwupdate, signal
> + * failed write with a 1 to keep created but not
> + * written files
> */
> - i_size_write(inode, 0);
> + i_size_write(inode, 1);
> } else {
> i_size_write(inode, datasize + sizeof(attributes));
> inode_set_mtime_to_ts(inode,
> inode_set_ctime_current(inode));
> @@ -124,7 +125,8 @@ static int efivarfs_file_release(struct inode
> *inode, struct file *file)
> struct efivar_entry *var = inode->i_private;
>
> inode_lock(inode);
> - var->removed = (--var->open_count == 0 && i_size_read(inode)
> == 0);
> + /* FIXME: temporary work around for fwupdate */
> + var->removed = (--var->open_count == 0 && i_size_read(inode)
> == 1);
> inode_unlock(inode);
>
> if (var->removed)
> --
> 2.43.0
>
>
