The automounter is a tool to automatically mount remote file systems
on demand. This implementation is partially kernel-based to reduce
overhead in the already-mounted case; this is unlike the BSD
automounter (amd), which is a pure user space daemon.

To use the automounter you need the user-space tools from the autofs
package; you can find the location in Documentation/Changes.
You also want to answer Y to "NFS file system support", below.

If you want to use the newer version of the automounter with more
features, say N here and say Y to "Kernel automounter v4 support",
below.

To compile this support as a module, choose M here: the module will be
called autofs.

If you are not a part of a fairly large, distributed network, you
probably do not need an automounter, and can say N here.

source code:

fs/autofs/