VM pressure. The reason is that in some codepaths pointers to stack
variables were passed from one thread to another.
In collaboration with: pho
Reported by: pho's stress2 suite
Sponsored by: iXsystems inc.
file servers fail to do it in the right way.
New NFLUSHWIRE flag marks pending flush request(s).
NB: not all cases covered by this commit.
Obtained from: Darwin