Can't create new file on a shared folder as root

[kiorky_]

I'm trying to mount the host's /etc and write to it from a guest. I can read, and edit files but cant delete or create others.

versions:

VBoxManage --version
4.3.4r91027

root@devhost3:/home/vagrant# modinfo vboxguest
filename:       /lib/modules/3.11.0-15-generic/updates/dkms/vboxguest.ko
version:        4.3.4
license:        GPL
description:    Oracle VM 

mountpoint:

root@devhost3:/home/vagrant# mount|grep hostetc
hostetc on /mnt/parent_etc/ type vboxsf (rw)

R/U:

root@devhost3:/mnt/parent_etc# ls foo hosts
foo  hosts
root@devhost3:/home/vagrant# touch /mnt/parent_etc/hosts
root@devhost3:/home/vagrant#

C/D:

root@devhost3:/home/vagrant# touch /mnt/parent_etc/azerty
touch: cannot touch '/mnt/parent_etc/azerty': Protocol error
root@devhost3:/mnt/parent_etc# rm foo
rm: cannot remove 'foo': Operation not permitted

[aeichner]

Please reopen if still relevant with a recent VirtualBox release.