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From: Rob Landley <rob@landley.net>
To: David Lang <david.lang@digitalinsight.com>,
	Linus Torvalds <torvalds@osdl.org>
Cc: Andries Brouwer <aebr@win.tue.nl>, Rob Love <rml@ximian.com>,
	Pascal Schmidt <der.eremit@email.de>,
	linux-kernel@vger.kernel.org, Greg KH <greg@kroah.com>
Subject: Re: udev and devfs - The final word
Date: Sun, 4 Jan 2004 21:48:24 -0600	[thread overview]
Message-ID: <200401042148.24742.rob@landley.net> (raw)
In-Reply-To: <Pine.LNX.4.58.0401041903290.6089@dlang.diginsite.com>

On Sunday 04 January 2004 21:06, David Lang wrote:
> 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.

NFS always struck me as a peverse design.  "The fileserver must be stateless 
with regard to clients, even though maintainging state is what a filesystem 
DOES, and the point of the thing is to export a filesystem."  Okay...  (If it 
was exporting read-only filesystems with no locking of any kind, maybe they'd 
have a point, but come on guys...)

So here's an example of where the fileserver _does_ expect to maintain 
non-file state across reboots.  "Ooh, the device node we're exporting is part 
of the ID, gee, we missed one!"

So why, exactly, can the NFS server not maintain whatever extra state it needs 
to remember between reboots in a filesystem?  (Not even necessarily the one 
it's exporting, just some rc file something under /var.)  The device node it 
was exporting USED to be in the filesystem, you know, ala mknod.  Now that 
the kernel's not keeping that stable, have the #*%(&# server generate a 
number and make a note of it somewhere.  (Is requiring an NFS server to have 
access to persistent storage too much to ask?)

Personally, I could never figure out why Samba servers are in userspace but 
NFS servers seem to want to live in the kernel.  I can almost secure a samba 
server for access to the outside world, but a NFS system that isn't behind a 
firewall automatically says to me "this machine has already been compromised 
eight ways from sunday within five minutes of being exposed to the internet".  
Call me paranoid...

Rob


  reply	other threads:[~2004-01-05  3:49 UTC|newest]

Thread overview: 169+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <18Cz7-7Ep-7@gated-at.bofh.it>
2003-12-31  3:05 ` udev and devfs - The final word Pascal Schmidt
2003-12-31 19:23   ` Greg KH
2003-12-31 20:19     ` Rob Love
2003-12-31 22:01       ` Nathan Conrad
2003-12-31 22:20         ` Rob Love
2003-12-31 21:45           ` Tommi Virtanen
2003-12-31 23:10             ` Rob Love
2003-12-31 21:52               ` Tommi Virtanen
2004-01-02  0:17                 ` Hollis Blanchard
2004-01-02  0:36                   ` viro
2004-01-03  6:04                   ` Greg KH
2003-12-31 22:55           ` viro
2003-12-31 23:05             ` Rob Love
2003-12-31 23:48             ` Andreas Dilger
2004-01-07 10:15             ` Olaf Hering
2004-01-07 11:18               ` viro
2004-01-07 13:00                 ` Olaf Hering
2004-01-07 13:26                   ` viro
2004-01-07 13:27                     ` Olaf Hering
2004-01-01  0:15       ` Andries Brouwer
2004-01-01  0:31         ` Rob Love
2004-01-01 12:34           ` Rob Landley
2004-01-01 15:22             ` Rob Love
2004-01-01 15:48               ` Andries Brouwer
2004-01-01 15:54                 ` Rob Love
2004-01-02 20:42                   ` Linus Torvalds
2004-01-03  3:00                     ` Andries Brouwer
2004-01-03  4:46                       ` Linus Torvalds
2004-01-03 13:10                         ` Andries Brouwer
2004-01-03 22:27                           ` Linus Torvalds
2004-01-03 23:08                             ` Andries Brouwer
2004-01-04  1:16                               ` Mark Mielke
2004-01-04  1:54                                 ` Valdis.Kletnieks
2004-01-04 18:44                                   ` Mark Mielke
2004-01-04  2:09                               ` Linus Torvalds
2004-01-04  2:49                                 ` Andries Brouwer
2004-01-04  3:04                                   ` Linus Torvalds
2004-01-04  4:36                                     ` Pentium 4 HT SMP Ananda Bhattacharya
2004-01-04  5:55                                       ` Martin J. Bligh
2004-01-04 13:21                                     ` udev and devfs - The final word Andries Brouwer
2004-01-04 21:05                                       ` Linus Torvalds
2004-01-04 22:01                                         ` Andries Brouwer
2004-01-04 22:37                                           ` viro
2004-01-05  1:02                                             ` Mark Mielke
2004-01-05  2:24                                               ` Valdis.Kletnieks
2004-01-05  2:29                                             ` Andries Brouwer
2004-01-05  3:42                                               ` viro
2004-01-04 22:37                                           ` Helge Hafting
2004-01-04 23:35                                           ` Valdis.Kletnieks
2004-01-05  1:43                                             ` Jeremy Maitin-Shepard
2004-01-05  1:47                                               ` st_dev:st_ino (was: Re: udev and devfs - The final word) Mark Mielke
2004-01-05  2:02                                                 ` st_dev:st_ino Jeremy Maitin-Shepard
2004-01-05  3:14                                                   ` st_dev:st_ino viro
2004-01-05  1:58                                               ` udev and devfs - The final word viro
2004-01-05  2:12                                                 ` Jeremy Maitin-Shepard
2004-01-05  2:52                                           ` Linus Torvalds
2004-01-05  3:06                                             ` David Lang
2004-01-05  3:48                                               ` Rob Landley [this message]
2004-01-05  4:52                                                 ` Trond Myklebust
2004-01-05  7:03                                                   ` [offtopic] " Rob Landley
2004-01-05 12:07                                                     ` Trond Myklebust
2004-01-05 15:13                                                 ` Mark Mielke
2004-01-05 16:36                                                   ` Andreas Schwab
2004-01-05 22:18                                                     ` Mark Mielke
2004-01-05  3:07                                             ` Daniel Jacobowitz
2004-01-05  3:33                                               ` Linus Torvalds
2004-01-05  3:50                                                 ` viro
2004-01-05  4:02                                                   ` Linus Torvalds
2004-01-05  4:38                                                     ` viro
2004-01-05  4:52                                                       ` Linus Torvalds
2004-01-05  6:11                                                         ` viro
2004-01-05  7:47                                                         ` Greg KH
2004-01-05 11:15                                                           ` Vojtech Pavlik
2004-01-05 20:11                                                             ` Theodore Ts'o
2004-01-05 21:06                                                               ` Vojtech Pavlik
2004-01-05 22:22                                                                 ` Theodore Ts'o
2004-01-06  0:14                                                                 ` Rob Landley
2004-01-06 17:28                                                                   ` [OT] " Disconnect
2004-01-11 22:12                                                         ` Ed L Cashin
2004-01-05  5:26                                                       ` Eric W. Biederman
2004-01-05  7:39                                                       ` Greg KH
2004-01-07  9:57                                                     ` Pavel Machek
2004-01-05 12:27                                                 ` Andries Brouwer
2004-01-05 16:13                                                   ` Linus Torvalds
2004-01-05 17:29                                                     ` Vojtech Pavlik
2004-01-05 17:33                                                       ` Linus Torvalds
2004-01-05 17:52                                                       ` Davide Libenzi
2004-01-05 18:03                                                         ` Linus Torvalds
2004-01-05 18:09                                                         ` Hugo Mills
2004-01-05 19:10                                                         ` Paul Rolland
2004-01-05 19:52                                                     ` Andries Brouwer
2004-01-05 20:38                                                       ` Linus Torvalds
2004-01-05 22:17                                                         ` Shawn
2004-01-05 22:25                                                           ` Mark Mielke
2004-01-05 23:05                                                             ` Shawn
2004-01-05 23:23                                                               ` Shawn
2004-01-06  0:43                                                               ` Greg KH
2004-01-06  0:53                                                                 ` Shawn
2004-01-05 23:13                                                         ` Andries Brouwer
2004-01-05 23:32                                                           ` Linus Torvalds
2004-01-06  0:59                                                             ` viro
2004-01-06  1:17                                                               ` Linus Torvalds
2004-01-06  4:28                                                                 ` viro
2004-01-06  5:07                                                                   ` Linus Torvalds
2004-01-06  1:06                                                             ` Andries Brouwer
2004-01-06 15:00                                                               ` Mark Mielke
2004-01-06  0:00                                                           ` Greg KH
2004-01-06  1:41                                                             ` Andries Brouwer
2004-01-07 17:14                                                               ` Greg KH
2004-01-06  0:31                                                           ` Rob Landley
2004-01-06  7:14                                                       ` Vojtech Pavlik
2004-01-06  0:36                                                     ` Silly udev script [was Re: udev and devfs - The final word] Greg KH
2004-01-05  7:44                                             ` udev and devfs - The final word James H. Cloos Jr.
2004-01-05  7:45                                               ` Nigel Cunningham
2004-01-05 11:01                                                 ` Robin Rosenberg
2004-01-05 12:39                                                   ` Nigel Cunningham
2004-01-05 14:31                                                     ` IRQ disabled on linux 2.6.1-rc1-mm1 Mainak Mandal _00007001_
2004-01-07 13:39                                                     ` udev and devfs - The final word Robin Rosenberg
2004-01-07 17:16                                                       ` Nigel Cunningham
2004-01-05  9:06                                               ` Valdis.Kletnieks
2004-01-05  4:15                                           ` Peter Chubb
2004-01-05  4:42                                             ` Linus Torvalds
2004-01-03 18:34                         ` Wrapping jiffies [was Re: udev and devfs - The final word] Pavel Machek
2004-01-01 19:43             ` udev and devfs - The final word Kai Henningsen
2004-01-02  7:26               ` Rob Landley
2004-01-04  8:57                 ` Greg KH
2004-01-04  9:43                   ` Rob Landley
2004-01-02  0:17             ` Maciej Zenczykowski
     [not found]               ` <20040102103104.GA28168@mark.mielke.cc>
2004-01-03  6:07                 ` Greg KH
2004-01-03  6:51                   ` Valdis.Kletnieks
2004-01-03 11:57                     ` Ian Kent
2004-01-03 22:08                     ` Greg KH
2004-01-07 10:23             ` Olaf Hering
2004-01-01 23:14           ` Rob
2004-01-02  3:53             ` Tyler Hall
2004-01-01 16:17     ` Pascal Schmidt
2004-01-01 20:03       ` Greg KH
2004-01-08 13:53 "Andrey Borzenkov" 
2004-01-08 15:40 ` Ian Kent
2004-01-08 17:26   ` Diego Calleja
2004-01-08 19:25     ` Andrey Borzenkov
2004-01-08 22:40       ` Alex Goddard
2004-01-09  7:03         ` "Andrey Borzenkov" 
2004-01-08 18:14   ` Alex Goddard
2004-01-08 18:35     ` Alex Goddard
2004-01-08 19:22     ` Andrey Borzenkov
2004-01-09  8:51 ` Helge Hafting
  -- strict thread matches above, loose matches on Subject: below --
2004-01-08 13:05 "Andrey Borzenkov" 
2004-01-06  1:20 Paul Zimmerman
     [not found] <fa.flhsork.uka2hg@ifi.uio.no>
     [not found] ` <fa.hv9hpq7.1l1q9p3@ifi.uio.no>
2004-01-01 19:53   ` walt
2004-01-01 21:53     ` Martin Schlemmer
2004-01-01 16:59 Shaheed
     [not found] <fa.af64864.ugabhg@ifi.uio.no>
     [not found] ` <fa.de7jae9.1jk0pjt@ifi.uio.no>
2003-12-31 22:17   ` walt
2004-01-01  2:03     ` Martin Schlemmer
2004-01-01  2:05       ` Martin Schlemmer
2003-12-31  0:29 Greg KH
2003-12-31  0:53 ` Prakash K. Cheemplavam
2003-12-31 19:17   ` Greg KH
2004-01-02 16:45     ` Shawn
2003-12-31 12:43 ` Paulo Marques
2004-01-01  1:18 ` Helge Hafting
2004-01-03  5:59   ` Greg KH
2004-01-03 15:22     ` Helge Hafting
2004-01-03 21:18       ` viro
2004-01-03 22:11       ` Greg KH
     [not found]     ` <20040103140140.3b848e9f.witukind@nsbm.kicks-ass.org>
2004-01-03 22:16       ` Greg KH
2004-01-03 22:33         ` Christoph Hellwig
2004-01-02 17:54 ` Andreas Jellinghaus
2004-01-02 18:19   ` Shawn

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