K 10
svn:author
V 3
mjg
K 8
svn:date
V 27
2014-07-06T22:56:34.718223Z
K 7
svn:log
V 323
MFC r267755:

Don't take filedesc lock in fdunshare().

We can read refcnt safely and only care if it is equal to 1.

If it could suddenly change from 1 to something bigger the code would be
buggy even in the previous form and transitions from > 1 to 1 are equally racy
and harmless (we copy even though there is no need).

END