of stat(2) calls by keeping an eye of the number of links a directory
has. It assumes that each subdirectory will have a hard link to its
parent, to represent the ".." node, and stops calling stat(2) when
all links are accounted for in a given directory.
This assumption is really only valid for UNIX-like filesystems: A
concrete example is NTFS. The NTFS "i-node" does contain a link
count, but most/all directories have a link count between 0 and 2
inclusive. The end result is that find on an NTFS volume won't
actually traverse the entire hierarchy of the directories passed
to it. (Those with a link count of two are not traversed at all)
The fix checks the "UFSness" of the filesystem before enabling the
optimisation.
Reviewed By: Tim Kientzle (kientzle@)
ea85333e1c