Ok, so mv gets slower for big trees... and open() gets faster for deep
trees. Previously, open in current directory was one atomic read of
directory entry, now it has to read directory, and its parent, and its
parent parent, and its...
(Or am I wrong and getting full path does not need to bring anything
in, not even in cache-cold case?)
So, proposed solution has different performance tradeoffs, but should
still be a win -- opens are more common than moves.
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html