Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265862AbUAEDGO (ORCPT ); Sun, 4 Jan 2004 22:06:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265863AbUAEDGO (ORCPT ); Sun, 4 Jan 2004 22:06:14 -0500 Received: from [209.195.52.120] ([209.195.52.120]:9683 "HELO warden2.diginsite.com") by vger.kernel.org with SMTP id S265862AbUAEDGG (ORCPT ); Sun, 4 Jan 2004 22:06:06 -0500 From: David Lang To: Linus Torvalds Cc: Andries Brouwer , Rob Love , rob@landley.net, Pascal Schmidt , linux-kernel@vger.kernel.org, Greg KH Date: Sun, 4 Jan 2004 19:06:00 -0800 (PST) Subject: Re: udev and devfs - The final word In-Reply-To: Message-ID: References: <20040103040013.A3100@pclin040.win.tue.nl> <20040103141029.B3393@pclin040.win.tue.nl> <20040104000840.A3625@pclin040.win.tue.nl> <20040104034934.A3669@pclin040.win.tue.nl> <20040104142111.A11279@pclin040.win.tue.nl> <20040104230104.A11439@pclin040.win.tue.nl> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3155 Lines: 78 Linus, what Andries is saying is that if you export a directory (say /home) the process of exporting it somehow uses the /dev device number so if the server reboots and gets a different device number for the partition that /home is on the clients won't see it as the same export, breaking the NFS requirement that a server can be rebooted. I don't agree with him becouse if the NFS server does include /dev info in what it shows to the outside world it's already broken. David Lang On Sun, 4 Jan 2004, Linus Torvalds wrote: > Date: Sun, 4 Jan 2004 18:52:56 -0800 (PST) > From: Linus Torvalds > To: Andries Brouwer > Cc: Rob Love , rob@landley.net, > Pascal Schmidt , linux-kernel@vger.kernel.org, > Greg KH > Subject: Re: udev and devfs - The final word > > > > On Sun, 4 Jan 2004, Andries Brouwer wrote: > > > > Surprise! Are you leaving POSIX? Or ditching NFS? > > Or demanding that NFS servers must never reboot? > > Ok, Andries, time for you to take a deep breath, and calm down. Because > your arguments are getting ridiculous in the extreme. > > A NFS server is sure as hell not going to export _its_ dynamic /dev to its > clients. That would be not just stupid, but crazy. Next you tell me that > you were using devfs and exporting that over NFS. > > A NFS server is going to export something _totally_ different than its own > /dev directory - it needs to be _client_-specific anyway. That's true with > stable numbers too, btw - ever tried to mount a Solaris /dev on a Linux > client? No workee. > > > A common Unix idiom is testing for the identity > > of two files by comparing st_ino and st_dev. > > A broken idiom? > > No. It still works. Even if the device numbers change across reboots. > > Why? Becuase that _program_ sure as hell isn't running across a reboot. > > And again, this is not something we haven't seen before. Have you ever > looked at the "st_dev" values? Try once - look at what it returns for a > NFS-mounted filesystem. Ponder. Notice how it already is NOT stable across > reboots. > > In other words, the stuff you're complaining about is all stuff that > nobody has _ever_ been able to rely on, and that has nothign to do with > udev or anythign else. It all just shows how 100% right I am for saying > that you cannot rely on stable numbers. > > So I repeat: calm down, and think it through. > > Linus > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- "Debugging is twice as hard as writing the code in the first place. Therefore, if you write the code as cleverly as possible, you are, by definition, not smart enough to debug it." - Brian W. Kernighan - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/