From Bill Irwin

The simple_link(), simple_unlink(), simple_rename(),
simple_sync_file(), simple_rmdir(), and simple_empty() functions are
easy to duplicate.  Basically, I duplicated them in an fs patch of
mine, and Linus told me to put them in libfs.c

Pat Mochel has acked the changes for driverfs (in that he'll convert
the stuff over when they're available from libfs), and my hugetlbfs
implementation was the thing that spurred the whole incident.