Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762218AbXJYXwl (ORCPT ); Thu, 25 Oct 2007 19:52:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754006AbXJYXwc (ORCPT ); Thu, 25 Oct 2007 19:52:32 -0400 Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:34505 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753187AbXJYXwb (ORCPT ); Thu, 25 Oct 2007 19:52:31 -0400 Date: Fri, 26 Oct 2007 09:52:06 +1000 From: David Chinner To: Miklos Szeredi Cc: dgc@sgi.com, staubach@redhat.com, akpm@linux-foundation.org, hch@infradead.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH] VFS: new fgetattr() file operation Message-ID: <20071025235206.GA995458@sgi.com> References: <471F4254.9040206@redhat.com> <471F5EA2.8060203@redhat.com> <20071025224235.GZ995458@sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1802 Lines: 58 On Fri, Oct 26, 2007 at 01:10:14AM +0200, Miklos Szeredi wrote: > > On Wed, Oct 24, 2007 at 05:27:04PM +0200, Miklos Szeredi wrote: > > > > >> Wouldn't you be better off by attempting to implement an "open > > > > >> by ino" operation and an operation to get the generation count > > > > >> for the file and then modifying the network protocol of interest > > > > >> to use these as identifiers for the file to be manipulated? > > > > >> > > > > > > > > > > You mean an "open by inode" on the userspace API? My guess, it > > > > > wouldn't get very far. > > > > > > > > This isn't a new idea and has been implemented on a variety of > > > > different systems. > > > > > > Like? > > > > XFS. > > > > 'man open_by_handle' > > Doesn't seem widely used, with 600 something google hits. from the man page: "They are intended for use by a limited set of system utilities such as backup programs." It also gets used by HSMs and so it is current, tested and is not going away.... > And in this > old thread Linus is not entirely enthusiastic about the concept: > > http://lkml.org/lkml/1999/1/11/244 That was "open by inode number", AFAICT. A handle is an opaque blob that can be an arbitrary length defined by the filesystem. You have to convert a fd or path to a handle first before you can use it later, so any filesystem can implement it... i.e. it is exactly what this (unanswered) post suggested: http://lkml.org/lkml/1999/1/13/186 Just my 2c worth.... Cheers, Dave. -- Dave Chinner Principal Engineer SGI Australian Software Group - 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/