losetup: no warning on multiple associations with the same file

Binary package hint: util-linux

losetup sees no problem creating multiple association for a single source device, i.e. /tmp/file1 -> /dev/loop0 and /tmp/file1 -> /dev/loop1. I understand, this is the desired behaviour as you might want to map one part of a file to loop0 and another to loop1. This works badly in the ubuntu case, however: Adding an association with losetup creates a udev-event which is propagated and causes nautilus to offer you to mount the newly detected device. Now, if you accidently associate a source file to two loop devices (i.e. by typing "losetup -f sourcefile" twice) and accidently mount both of them (i.e. out of curiosity what the second device is) you may very well loose your data.

1) Ubuntu Release:
Description: Ubuntu 10.04 LTS
Release: 10.04

2) Package Version:
mount 2.17.2-0ubuntu1

3) Expected Behaviour:
When creating an association for a source file which is already in use, losetup should warn the user. I.e. ask the user to repeat the command with a "--force" flag.

4) Current Behaviour:
No warning whatsoever is produced while creating multiple associations for a single source file.