libfile-nfslock-perl 1.21-1 (i386 binary) in ubuntu trusty

 Program based on the concept of hard linking of files being atomic across
 NFS. This concept was mentioned in Mail::Box::Locker. Some ideas are
 taken from there -- particularly the idea of creating a random local file,
 hard linking a common file to the local file, and then checking the nlink
 status.
 .
 File::NFSLock was written to be light, generic, and fast.