While looking over the filesystem snapshot code from FreeBSD I discovered a
somewhat strange behaviour of namei():

If called for a DOT directory ("." or "...path/.") it returns with

    nd.ni_dvp == nd.ni_vp

Even if called with LOCKPARENT flag both (identical) vnodes are not locked.
This leads to a bunch of code like

    if (nd.ni_dvp == nd.ni_vp)
	vrele(nd.ni_dvp);
    else
	vput(nd.ni_dvp);

Is there a reason why the parent directory (nd.ni_dvp) is returned unlocked?

If the parent directory was locked this code would become as simple as

    vput(nd.ni_dvp);

-- 
Juergen Hannken-Illjes - hannken@eis.cs.tu-bs.de - TU Braunschweig (Germany)