named pipes memory leak?

[Don Lewis]

On 11 Nov, Lukas Ertl wrote:
> On Tue, 11 Nov 2003, Lukas Ertl wrote:
> 
>> Unfortunately, we are still seeing a problem here: we are running uvscan
>> (virus scanner), and while running it we are still seeing increasing unpcb
>> usage and orphaned unix domain sockets.
>>
>> We added some debug printfs to the fifo routines and found out that
>> fifo_cleanup is called from fifo_close with a vnode which has v_usecount
>> == 2 so the socket close calls aren't reached.
> 
> Sorry, I probably missed an important part: we're creating the FIFOs on
> nullfs mounts - the test script works great on plain UFS mounts, but the
> null layer seems to VREF the vnode once again, so v_usecount is 2, thus it
> is missong the check in fifo_cleanup().

I just committed a fix for this.  Fifo_vnops.c 1.91 should not leak
memory and sockets when used with nullfs.