Re: [PATCH v4 2/3] init/do_mounts.c: create second mount for initramfs

[Menglong Dong <menglong8.dong@xxxxxxxxx>]

On Thu, Jun 3, 2021 at 9:30 PM Christian Brauner
<christian.brauner@xxxxxxxxxx> wrote:
>
[...]
>
> In fact you seem to be only using this struct you're introducing in this
> single place which makes me think that it's not needed at all. So what's
> preventing us from doing:
>
> > +
> > +     return do_mount_root(root->dev_name,
> > +                          root->fs_name,
> > +                          root_mountflags & ~MS_RDONLY,
> > +                          root_mount_data);
> > +}
>
> int __init prepare_mount_rootfs(void)
> {
>         if (is_tmpfs_enabled())
>                 return do_mount_root("tmpfs", "tmpfs",
>                                      root_mountflags & ~MS_RDONLY,
>                                      root_mount_data);
>
>         return do_mount_root("ramfs", "ramfs",
>                              root_mountflags & ~MS_RDONLY,
>                              root_mount_data);
> }

It seems to make sense, but I just feel that it is a little hardcode.
What if a new file system
of rootfs arises? Am I too sensitive?

[...]
>
> This is convoluted imho. I would simply use two tiny helpers:
>
> void __init finish_mount_rootfs(void)
> {
>         init_mount(".", "/", NULL, MS_MOVE, NULL);
>
>         if (ramdisk_exec_exist())
>                 init_chroot(".");
> }
>
> void __init revert_mount_rootfs(void)
> {
>         init_chdir("/");
>         init_umount(".", 0);
> }
>

This looks nice.


Thanks!
Menglong Dong