weird mount behavior

[harrim4n]

I just noticed a weird mounting behavior as well on my DockStar as on my Pogoplug. I have one USB-HDD and the USB-drive with the OS connected to the plug and only an USB-drive with the OS on the DockStar. Now if I do a mount on the DockStar it shows me that /dev/root is mounted on /. But if I do a ls it says that /dev/root doesn't exist.
$this->bbcode_second_pass_code('', '
[harrim4n@DockStar ~]$ mount
/dev/root on / type ext4 (rw,relatime,data=ordered)
')
$this->bbcode_second_pass_code('', '
[harrim4n@DockStar ~]$ sudo ls /dev/root
ls: cannot access /dev/root: No such file or directory
')
The same applies to the Plug. Also the USB-HDD (with one partition) is suddenly /dev/sda1 and the partition of the USB-drive which contains / is /dev/sdb1, which can also mounted in some other directory, even in multiple directories at once. And two devices can be mounted in one directory.
$this->bbcode_second_pass_code('', '
/dev/root on / type ext2 (rw,relatime,user_xattr,acl,barrier=1)
[...]
/dev/sdb1 on /tmp/Data type ext2 (rw,relatime,user_xattr,acl,barrier=1)
/dev/sda1 on /media/Data type ext2 (rw,relatime,user_xattr,acl,barrier=1)
/dev/sda1 on /tmp/Data type ext2 (rw,relatime,user_xattr,acl,barrier=1)
')

I really don't know if this is as it is supposed to be but it really freaks me out.
Any ideas?

harrim4n

[WarheadsSE]

/dev/root is essentially "that thing I got in the 'rootfs=blah' from the commandline"

Neither it, or any block device is intended to be accessed via ls...

[harrim4n]

I see. But why did this suddenly occur? All the time /dev/sda2 (or /dev/sda1) were mounted on /. I didn't change anything in the uboot, so that can't be the issue. Maybe some update changed the behavior or something? And still, this doesn't explain why two devices can be mounted into one directory, or is this intended? Also, why can I mount the partition that contains the OS while the system is running? Wouldn't the filesystem break if I edit it at the same time as another process?

[moonman]

This has always been the behavior. You probably never npticed before. The kernel comes with aufs patch. look it up