Re: [PATCH v6 2/2] init/do_mounts.c: create second mount for initramfs

Menglong Dong
2021-06-17T03:59:44Z

Hello,

On Mon, Jun 07, 2021 at 05:15:24AM -0700, menglong8.dong@gmail.com wrote:
> On Mon, Jun 07, 2021 at 12:31:47PM +0200, Christian Brauner wrote:
> > On Sat, Jun 05, 2021 at 10:47:07PM +0800, Menglong Dong wrote:
> [...]
> > >
> > > I think it's necessary, as I explained in the third patch. When the rootfs
> > > is a block device, ramfs is used in init_mount_tree() unconditionally,
> > > which can be seen from the enable of is_tmpfs.
> > >
> > > That makes sense, because rootfs will not become the root if a block
> > > device is specified by 'root' in boot cmd, so it makes no sense to use
> > > tmpfs, because ramfs is more simple.
> > >
> > > Here, I make rootfs as ramfs for the same reason: the first mount is not
> > > used as the root, so make it ramfs which is more simple.
> >
> > Ok. If you don't mind I'd like to pull and test this before moving
> > further. (Btw, I talked about this at Plumbers before btw.)
> > What did you use for testing this? Any way you can share it?
>

I notice that it have been ten days, and is it ok to move a little
further? (knock-knock :/)

Thanks!
Menglong Dong

> Ok, no problem definitely. I tested this function in 3 way mainly:
>
> 1. I debug the kernel with qemu and gdb, and trace the the whole
> process, to ensure that there is no abnormal situation.
> 2. I tested pivot_root() in initramfs and ensured that it can be
> used normally. What's more, I also tested docker and ensured
> container can run normally without 'DOCKER_RAMDISK=yes' set in
> initramfs.
> 3. I tried to enable and disable CONFIG_INITRAMFS_MOUNT, and
> ensured that the system can boot successfully from initramfs, initrd
> and sda.
>
> What's more, our team is going to test it comprehensively, such as
> ltp, etc.
>
> Thanks!
> Menglong Dong
>