From: Rob Landley [mailto:rob@landley.net]
Sent: Tuesday, July 19, 2022 1:51 PM
On 7/19/22 01:55, Roberto Sassu wrote:

quoted

quoted

Thank you, I have tested that patch but the problem remained. Here is my
command line, I wonder if there is something wrong.

Kernel command line: rw rootfstype=initramtmpfs root=/dev/ram0
initrd=0x500000000 rootwait

It is just initramtmpfs, without rootfstype=.

Whoever wrote that patch really doesn't understand how this stuff works. I can
tell from the name.

Hi Rob

surely, I should have been more careful in choosing the name of
the option.

Technically, initramfs is the loader, I.E. "init ramfs". The filesystem instance
is called "rootfs" (hence the name in /proc/mounts when the insane special case
the kernel added doesn't hide information from people, making all this harder to
understand for no obvious reason).

Ok, thanks for the explanation.

ramfs and tmpfs are two different filesystems that COULD be used to implement
rootfs. (Last I checked they were the only ram backed filesystems in Linux.)

Yes, that part I got it.

If a system administrator says they're going to install your server's root
partition using the "reiserxfs" filesystem, I would not be reassured.

Definitely.

[...]

P.P.S. If you want to run a command other than /init out of initramfs or initrd,
use the rdinit=/run/this option. Note the root= overmount mechanism is
completely different code and uses the init=/run/this argument instead, which
means nothing to initramfs. Again, specifying root= says we are NOT staying in
initramfs.

Sorry, it was some time ago. I have to go back and see why we needed
a separate option. Maybe omitting root= was impacting on mounting
the real root filesystem. Will get that information.

Intuitively, given that root= is consumed for example by dracut, it seems
a safer choice to have an option to explicitly choose the desired filesystem.

Roberto