Date: Sun, 11 Oct 2020 09:12:43 -0600 From: Warner Losh <imp@bsdimp.com> To: Kyle Evans <kevans@freebsd.org> Cc: Alexey Dokuchaev <danfe@freebsd.org>, Toomas Soome <tsoome@me.com>, 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: r366626 - head/sbin/reboot Message-ID: <CANCZdfpL0ajtSjFYj-5p3Si_vsV-4Q_qHkNY8oaVDsZ%2BZwQcLg@mail.gmail.com> In-Reply-To: <CACNAnaH%2BocNxvkXiiqa_13RRf5oT9O0jTjik2gw_83WHStXTeA@mail.gmail.com> References: <202010111040.09BAeCfg073782@repo.freebsd.org> <8601CC07-3A43-461A-915C-3CB68BADF41A@me.com> <20201011130151.GA32755@FreeBSD.org> <35355AD6-42C6-48A2-8FCF-A371A82D683A@me.com> <20201011133023.GA67893@FreeBSD.org> <CACNAnaH%2BocNxvkXiiqa_13RRf5oT9O0jTjik2gw_83WHStXTeA@mail.gmail.com>
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On Sun, Oct 11, 2020, 8:00 AM Kyle Evans <kevans@freebsd.org> wrote: > On Sun, Oct 11, 2020 at 8:30 AM Alexey Dokuchaev <danfe@freebsd.org> > wrote: > > > > On Sun, Oct 11, 2020 at 04:08:09PM +0300, Toomas Soome wrote: > > > > On 11. Oct 2020, at 16:01, Alexey Dokuchaev wrote: > > > >> ... > > > >> Also nextboot.conf not generic configuration file (such as > loader.conf > > > >> or loader.conf.local), but the implementation specific file, part of > > > >> special feature. > > > >> > > > >> That is, one should not assume the presence of nextboot.conf file, > make > > > >> assumptions about its content, or perform manual edits on it. > > > > > > > > Do we want it to be the second-class citizen like this? Would it > make > > > > better sense by documenting it more completely instead? > > > > > > It is not really about being second-class citizen, it really is about > if > > > and how we can implement the feature. With UFS there is a limited write > > > (write to existing, allocated disk blocks), with ZFS there is no write > to > > > file system at all. > > > > I see; that would explain why loader(8) replaces the "YES" -> > "NO"<space>, > > but I guess I'd have to read the discussion on -rc@ which lead to > r177062, > > because I don't see the reason for it to be removed (twice) if it's being > > disabled by the loader(8) earlier anyway. > > > > IMO both steps are important. You have to (at least try to) disable it > in case it doesn't get you all the way to multi-user, but then you > don't want the old contents of nextboot.conf being inadvertently used > on another boot if someone's habitually `nextboot -a`ing. > There were cases that were discussed when the geature went in that required it to be removed in some failure modes for full functionality. I don't recall if they were in the rc thread or somewhere else. And honestly, nextboot.conf is special in so many ways. We have no unlink in the loader for UFS and no write for ZFS or MSDOS. In those cases, the rm from rc is what you want (though lately we use a different mechanism for ZFS). So the docs were right before, in the big picture. The implementation detail now enshrined there is unwise. I'm not likely to remove it, but if UFS grows unlink in the future, this man page will need to change. Then again, all the loser man pages need a complete rewrite, or close to it. Warner >
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