svn commit: r348737 - head/sys/kern

[Alan Somers]

On Thu, Jun 6, 2019 at 11:35 AM Rodney W. Grimes
<freebsd at gndrsh.dnsmgr.net> wrote:
>
> > Author: asomers
> > Date: Thu Jun  6 15:04:50 2019
> > New Revision: 348737
> > URL: https://svnweb.freebsd.org/changeset/base/348737
> >
> > Log:
> >   Add a testing facility to manually reclaim a vnode
> >
> >   Add the debug.try_reclaim_vnode sysctl. When a pathname is written to it, it
> >   will be reclaimed, as long as it isn't already or doomed. The purpose is to
> >   gain test coverage for vnode reclamation, which is otherwise hard to
> >   achieve.
> >
> >   Add the debug.ftry_reclaim_vnode sysctl.  It does the same thing, except
> >   that its argument is a file descriptor instead of a pathname.
>
> Should not this all be wrapped in some #ifdef or other protection,
> is it really a good idea to have this on every single box running
> FreeBSD?

I initially thought so too, but kib thought that it could be useful
for debugging problems in the field.  The potential downside is
limited, because only root can write to the sysctls, and the
worse-case damage is similar to a "umount -f".

-Alan