What's going on with vnets and epairs w/ addresses?

Hi,

I have used scripts like the below for almost a decade and a half
(obviously doing more than that in the middle).  I haven't used them
much lately but given other questions I just wanted to fire up a test.

I have an end-November kernel doing the below my eapirs do not come back
to be destroyed (immediately).
I have to start polling for the jid to be no longer alive and not in
dying state (hence added the jls/ifconfig -l lines and removed the
error checking from ifconfig destroy).  That seems sometimes rather
unreasonably long (to the point I give up).

If I don't configure the addresses below this isn't a problem.

Sorry I am confused by too many incarnations of the code; I know I once
had a version with an async shutdown path but I believe that never made
it into mainline, so why are we holding onto the epairs now and not
nuking the addresses and returning them and are clean?

It's a bit more funny; I added a twiddle loop at the end and nothing
happened.  So I stop the script and start it again and suddenly another
jail or two have cleaned up and their epairs are back.  Something feels
very very wonky.  Play around with this and see ... and let me know if
you can reproduce this...  I quite wonder why some test cases haven't
gone crazy ...

/bz

------------------------------------------------------------------------
#!/bin/sh

set -e
set -x

js=`jail -i -c -n jl host.hostname=left.example.net vnet persist`
jb=`jail -i -c -n jr host.hostname=right.example.net vnet persist`

# Create an epair connecting the two machines (vnet jails).
ep=`ifconfig epair create | sed -e 's/a$//'`

# Add one end to each vnet jail.
ifconfig ${ep}a vnet ${js}
ifconfig ${ep}b vnet ${jb}

# Add an IP address on the epairs in each vnet jail.
# XXX Leave these out and the cleanup seems to work fine.
jexec ${js}  ifconfig ${ep}a inet  192.0.2.1/24
jexec ${jb}  ifconfig ${ep}b inet  192.0.2.2/24

# Clean up.
jail -r ${jb}
jail -r ${js}

# You want to be able to remove this line ...
set +e

# No epairs to destroy with addresses configured; fine otherwise.
ifconfig ${ep}a destroy
# echo $?

# Add this is here only as things are funny ...
# jls -av jid dying
# ifconfig -l

# end
------------------------------------------------------------------------

-- 
Bjoern A. Zeeb                                                     r15:7