Re: [PATCH 04/20] kbuild: scripts/install.sh: call sync before calling the bootloader installer

From: Masahiro Yamada <masahiroy@kernel.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Michal Marek <michal.lkml@markovi.net>,
	Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
	linux-arch <linux-arch@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 04/20] kbuild: scripts/install.sh: call sync before calling the bootloader installer
Date: Wed, 7 Apr 2021 20:03:18 +0900	[thread overview]
Message-ID: <CAK7LNAQ4ar1gM1+08EXUZYHvt38Bt_D+NZdhRyH8hfjecw2vEg@mail.gmail.com> (raw)
In-Reply-To: <20210407053419.449796-5-gregkh@linuxfoundation.org>

On Wed, Apr 7, 2021 at 2:34 PM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> It's good to ensure that the files are written out before calling the
> bootloader installer, as other architectures do, so call sync after
> doing the copying of the kernel and system map files.

I see 3 architectures that call 'sync' from install.sh

masahiro@grover:~/ref/linux$ find . -name install.sh  | xargs grep sync
./arch/nios2/boot/install.sh:sync
./arch/x86/boot/install.sh:       sync
./arch/m68k/install.sh:sync

As for nios2 and m68k, they do not call
any bootloader-specific setups.

> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
>  scripts/install.sh | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/scripts/install.sh b/scripts/install.sh
> index af36c0a82f01..92d0d2ade414 100644
> --- a/scripts/install.sh
> +++ b/scripts/install.sh
> @@ -52,12 +52,12 @@ if [ -x /sbin/"${INSTALLKERNEL}" ]; then exec /sbin/"${INSTALLKERNEL}" "$@"; fi
>  # Default install - same as make zlilo
>  install "$2" "$4"/vmlinuz
>  install "$3" "$4"/System.map
> +sync
>
>  if [ -x /sbin/lilo ]; then
>         /sbin/lilo
>  elif [ -x /etc/lilo/install ]; then
>         /etc/lilo/install
>  else
> -       sync
>         echo "Cannot find LILO."
>  fi
> --
> 2.31.1
>

Why do we need 'sync' before lilo invocation?

If you want to ensure everything is flushed
to a disk before this scripts exits,
adding 'sync' at the end of the script
makes more sense, in my opinion.

   if [ -x /sbin/lilo ]; then
          /sbin/lilo
   elif [ -x /etc/lilo/install ]; then
          /etc/lilo/install
   else
         echo "Cannot find LILO."
   fi

   sync

This goes aligned with nios2 and m68k.

--
Best Regards

Masahiro Yamada