The main goal of the Linux Trustees project is to create an advanced permission management system for Linux. The solution proposed is mainly inspired by the approach taken by Novell Netware and the Java security API. Special objects (called trustees) can be bound to every file or directory. The trustee object can be used to ensure that access to a file, directory, or directory with subdirectories is granted (or denied) to a certain user or group (or all except user or group). Trustees are like POSIX ACLs, but trustee objects can affect entire subdirectory trees, while ACLs a single file. Trustees works with the 2.6 Linux kernel.
mmounter tries to mimic the behaviour of MacOS with regards to automatic monitoring and mounting of the volumes in your system (CDs, ZIP disks, floppies, HDs) using their volume name as the mount point. It will optionally eject devices and let users mount/umount them. Currently mmounter supports ext2, ext3, iso9660 (CD), HFS, and VFAT. This tool is user-space only (doesn't require any kernel patching) and should be fairly portable.
muser lists processes which have a given directory (or cwd if not specified) as a parent of their current working directory (thus making it impossible to unmount that directory if it is a mount point). This script has overlapping functionality with the fuser program from the psmisc package, but has the advantage that it works on SMB mounts. Additionally, it provides a color, formatted listing of process IDs, executable names, current working directories, and the command lines used to run the programs. It works with varying-sized /proc/*/cwd fields.