5943f1a781
with low nmbclusters, we tie up too many mbclusters in the NFS duplicate request cache. This change limits the size of the dupreq cache to 1/2 the nmbclusters (and flaots in a range of [64, 2048]). MFC after 2 weeks. Reported by: Steve Kargl, David O'Brien Tested by: Steve Kargl