Date: Thu, 6 Jun 2019 11:28:20 -0700 (PDT) From: "Rodney W. Grimes" <freebsd@gndrsh.dnsmgr.net> To: John Baldwin <jhb@FreeBSD.org> Cc: Alan Somers <asomers@FreeBSD.org>, "Rodney W. Grimes" <rgrimes@FreeBSD.org>, src-committers <src-committers@FreeBSD.org>, svn-src-all <svn-src-all@FreeBSD.org>, svn-src-head <svn-src-head@FreeBSD.org> Subject: Re: svn commit: r348737 - head/sys/kern Message-ID: <201906061828.x56ISKJI059207@gndrsh.dnsmgr.net> In-Reply-To: <c6d9a869-d678-212b-0bc6-d0046f892e76@FreeBSD.org>
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[ Charset UTF-8 unsupported, converting... ] > On 6/6/19 10:39 AM, Alan Somers wrote: > > On Thu, Jun 6, 2019 at 11:35 AM Rodney W. Grimes > > <freebsd@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". > > A compromise might be to stick this in a kernel module instead of in the > base kernel. You could still kldload it in the field for debugging but > not necessarily have it directly available out of the box. Oh, yes, I like this solution, then avaliable on demand at anytime to anyone, but not present by default. > John Baldwin -- Rod Grimes rgrimes@freebsd.org
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