Implementation detail

The problem is that now `mv dir/ foo` is slow if dir/ is large. Every moved file must be checked against the database for multiple links and the new path updated. And we need foo to be fully resolved from the root of the filesystem. Alternatively, each link could be stored in the table as a (name, dirinode) pair and the path generated from the recursion over the dirinode (the mount point that the request was based in should probably be used as the "above the root" path prefix. The functionality could probably also be worked into the locate/updatedb tools.