Mounting ext2 sdcard partition causes I/O errors

So I am attempting to mount an ext2 partition on a pen drive to a tablet I have, the actually mount is done with: adb shell "mount -t ext2 /dev/block/sdb /mnt/ubuntu" This works fine and ubuntu is a folder I already created on the android device. Now when I go to access the files on that partition (the rootfs of a ubuntu install in fact) I end up with: root@android:/ # ls /storage/ubuntu lstat '/storage/ubuntu/android' failed: I/O error lstat '/storage/ubuntu/bin' failed: I/O error lstat '/storage/ubuntu/boot' failed: I/O error lstat '/storage/ubuntu/dev' failed: I/O error lstat '/storage/ubuntu/etc' failed: I/O error lstat '/storage/ubuntu/external_sd' failed: I/O error lstat '/storage/ubuntu/home' failed: I/O error lstat '/storage/ubuntu/lib' failed: I/O error lost+found lstat '/storage/ubuntu/media' failed: I/O error lstat '/storage/ubuntu/mnt' failed: I/O error lstat '/storage/ubuntu/opt' failed: I/O error lstat '/storage/ubuntu/proc' failed: I/O error lstat '/storage/ubuntu/root' failed: I/O error lstat '/storage/ubuntu/run' failed: I/O error lstat '/storage/ubuntu/sbin' failed: I/O error lstat '/storage/ubuntu/sdcard' failed: I/O error lstat '/storage/ubuntu/selinux' failed: I/O error lstat '/storage/ubuntu/srv' failed: I/O error lstat '/storage/ubuntu/sys' failed: I/O error lstat '/storage/ubuntu/tmp' failed: I/O error lstat '/storage/ubuntu/usr' failed: I/O error lstat '/storage/ubuntu/var' failed: I/O error