svn commit: r348737 - head/sys/kern

[Rodney W. Grimes]

[ Charset UTF-8 unsupported, converting... ]
> 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".

Things that are useful for diagnostics and debugging do not belong
on all production machines.  I could live with INVARIANTS so it
is only in all ^/head machines, but imho shipping this type of
stuff in -RELEASE is not a good idea.

> -Alan
-- 
Rod Grimes                                                 rgrimes at freebsd.org