Thanks alastairstevenson. I followed your suggestion and I got
# mount
rootfs on / type rootfs (rw)
/dev/root on / type ext2 (rw,relatime)
proc on /proc type proc (rw,relatime)
sysfs on /sys type sysfs (rw,relatime)
ramfs on /home type ramfs (rw,relatime)
udev on /dev type tmpfs (rw,relatime)...