illumos gate

hyprlofs is a filesystem that is a hybrid of lofs and tmpfs. Conceptually it
is similar to lofs, but unlike lofs, where each entry is a mountpoint managed
via mount, hyperlofs is managed via an ioctl which can be used in a single
syscall to setup/remove access to 1000s of entries at a time. The intention
is that this is a very fast, lightweight mechanism to provide transient
visibility to a large number of files and directories from across the system
under a single mountpoint.