Date: Wed, 7 Aug 2002 23:21:09 -0600 From: Scott Long <scott_long@btc.adaptec.com> To: Kelly Yancey <kbyanc@posi.net> Cc: Terry Lambert <tlambert2@mindspring.com>, "David E. Cross" <crossd@cs.rpi.edu>, fs@freebsd.org, guptar@cs.rpi.edu Subject: Re: vnodes (UFS journaling)? Message-ID: <20020808052109.GC47545@hollin.btc.adaptec.com> In-Reply-To: <20020807214625.C667-100000@gateway.posi.net> References: <3D51BE6F.298F0AF@mindspring.com> <20020807214625.C667-100000@gateway.posi.net>
next in thread | previous in thread | raw e-mail | index | archive | help
On Wed, Aug 07, 2002 at 09:57:42PM -0700, Kelly Yancey wrote: > On Wed, 7 Aug 2002, Terry Lambert wrote: > > > Kelly Yancey wrote: > > > > > > I believe he is trying to keep a journal, likely as a file on the > > > filesystem that is being journalled. I don't actually know, but that's > > > what I would guess. > > > > I understand that he's working on a journalling FS. > > > > I'm wondering what reaccessing vnodes has to do with journalling? > > > > A vnode is an in-core abstract representation of a file in > > a file system, that has a non-abstract real file association > > in the FS itself. A vnode doesn't know about the journalling > > taking place in the underlying FS -- and *shouldn't* know > > about it. The VFS interface layer is intended as a method of > > abstracting *exacly* this sort of implementation detail. > > > [ snip ] > > Yeah, I've read the Red Book too. :) I would guess that the vnode in > question is the vnode representing the journal file itself. How you journal > filesystem operations to a file on that very filesystem is beyond me, but I'm > sure the bright boys at RPI have figured it out...barring the problem that > David wrote -fs about and which we have conveniently neglected to answer. :) > > Kelly > I'll chime in and say that, as much as it pains me to admit, Terry is right =-). Manipualting the journal file from the vnode layer is the wrong way to go about this. However, if you want to push forward in a quick-n-dirty manner right now, you could probably hack up ufs_lookup() to not return a vnode for the journal file. Then you can keep your reference on the vnode and not worry about contention. That said, I'd really looking forward to seeing the results of your work. Scott To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20020808052109.GC47545>