From: David Chinner Subject: Re: [NFS] What's slated for inclusion in 2.6.24-rc1 from the NFS client git tree... Date: Mon, 8 Oct 2007 08:56:09 +1000 Message-ID: <20071007225609.GQ23367404@sgi.com> References: <1191454876.6726.32.camel@heimdal.trondhjem.org> <20071004085206.0a8e37b5@poseidon.drzeus.cx> <1191506450.6685.17.camel@heimdal.trondhjem.org> <30494.1191605410@turing-police.cc.vt.edu> <20071005141222.5afbb6b9.jlayton@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Valdis.Kletnieks@vt.edu, Peter Staubach , Andrew@sc8-sf-spam2-b.sourceforge.net, nfsv4@linux-nfs.org, linux-kernel@vger.kernel.org, Trond Myklebust , nfs@lists.sourceforge.net, Pierre Ossman , Morton To: Jeff Layton Return-path: In-Reply-To: <20071005141222.5afbb6b9.jlayton@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: On Fri, Oct 05, 2007 at 02:12:22PM -0400, Jeff Layton wrote: > On Fri, 05 Oct 2007 13:30:10 -0400 > Valdis.Kletnieks@vt.edu wrote: > > > On Thu, 04 Oct 2007 10:00:50 EDT, Trond Myklebust said: > > > > > How about a boot/module parameter to turn it on or off? > > > > > > I don't see any point in having a sysctl for something like this: either > > > you have legacy applications or you don't. It is not something that you > > > switch off as you go off to lunch. > > > > How does Joe Sysadmin tell if he has an affected legacy app or not? > > > > (The obvious "try it and see what breaks" is a non-starter for many places, > > because you too easily end up in a loop of "enable it, find 4-5 show stoppers, > > turn it off, fix them, lather rinse repease". Been there, done that, got > > the tshirt - a project I got dragged into involves a large storage array that > > appears to insist on exporting 64-bit stuff, and a large farm of clients that > > are very 64-bit unclean....) > > > > Note that "try it and see what breaks" isn't reliable either. If glibc > gets back a 64 bit inode number that just happens to fit in the 32-bit > field, then everything will work. You don't actually get an EOVERFLOW > until st_ino overflows the field, and that may not happen often enough > for testing this way to detect it... There's a damn easy way of testing this. Use XFS on a 64 bit Linux NFS server, mount is '-o inode64,ino64' and then export it to you client that is going to have problems. the "ino64" mount option guarantees that the userspace visible inode number is always > 32 bits in length.... Cheers, Dave. -- Dave Chinner Principal Engineer SGI Australian Software Group