Bug#742048: systemd-remount-fs.service fails for split-usr

[Sven Joachim]

On 2014-12-27 02:44 +0100, Michael Biebl wrote:

> It looks like we won't get initramfs-tools 0.118 with usr-mount support
> in the initramfs, as this created quite a few regressions which need to
> be dealt with first.
>
> I therefore think we need to workaround this issue in systemd and make
> sure systemd-remount-fs.service doesn't fail for split-usr setups.
> So marking this bug as RC and bumping the severity to serious.
>
> The patch might be as simple as the attached one. But we'll need to
> check if it doesn't cause any regressions with dracut and
> initramfs-tools 0.118, which actually do mount /usr in the initramfs.
>
> diff --git a/src/remount-fs/remount-fs.c b/src/remount-fs/remount-fs.c
> index 847637a..44cc959 100644
> --- a/src/remount-fs/remount-fs.c
> +++ b/src/remount-fs/remount-fs.c
> @@ -77,10 +77,9 @@ int main(int argc, char *argv[]) {
>                  int k;
>                  char *s;
>  
> -                /* Remount the root fs, /usr and all API VFS */
> +                /* Remount the root fs and all API VFS */
>                  if (!mount_point_is_api(me->mnt_dir) &&
> -                    !path_equal(me->mnt_dir, "/") &&
> -                    !path_equal(me->mnt_dir, "/usr"))
> +                    !path_equal(me->mnt_dir, "/"))
>                          continue;
>  
>                  log_debug("Remounting %s", me->mnt_dir);

I haven't looked at dracut, but with initramfs-tools 0.118 /usr is going
to end up being mounted readonly.  See the message for commit
d641934f7bf5ef36b31a57e0b7ec2db482940e11 in initramfs-tools:

,----
| debian/control: Add Breaks: systemd-sysv (<< 186)
|     
| If the kernel command line has 'ro' then the init system must
| remount /usr read-write, but systemd did not do this until
| version 186.
`----

Cheers,
       Sven