Interesting XFS Features

Direct I/O
Allows to perform non-cached, direct to userspace I/O
Ported to Linux together with XFS
Independent implementation in Linux 2.4.10
XFS ported to generic framework
Still advantages over generic implementation

Delayed Allocation
Very important for XFS performance
IRIX buffercache rewritten around it
Difficult to fit into 2.4 VM
2.5 way of buffer writeout helps a lot
Same concept used on 2.4 now too