Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965020AbVKVRSx (ORCPT ); Tue, 22 Nov 2005 12:18:53 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965022AbVKVRSx (ORCPT ); Tue, 22 Nov 2005 12:18:53 -0500 Received: from thunk.org ([69.25.196.29]:5251 "EHLO thunker.thunk.org") by vger.kernel.org with ESMTP id S965020AbVKVRSw (ORCPT ); Tue, 22 Nov 2005 12:18:52 -0500 Date: Tue, 22 Nov 2005 12:18:47 -0500 From: "Theodore Ts'o" To: Anton Altaparmakov Cc: Chris Adams , linux-kernel@vger.kernel.org Subject: Re: what is our answer to ZFS? Message-ID: <20051122171847.GD31823@thunk.org> Mail-Followup-To: Theodore Ts'o , Anton Altaparmakov , Chris Adams , linux-kernel@vger.kernel.org References: <20051122161712.GA942598@hiwaay.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1500 Lines: 30 On Tue, Nov 22, 2005 at 04:55:08PM +0000, Anton Altaparmakov wrote: > > That assumption is probably made because that's what POSIX and Single > > Unix Specification define: "The st_ino and st_dev fields taken together > > uniquely identify the file within the system." Don't blame code that > > follows standards for breaking. > > The standards are insufficient however. For example dealing with named > streams or extended attributes if exposed as "normal files" would > naturally have the same st_ino (given they are the same inode as the > normal file data) and st_dev fields. Um, but that's why even Solaris's openat(2) proposal doesn't expose streams or extended attributes as "normal files". The answer is that you can't just expose named streams or extended attributes as "normal files" without screwing yourself. Also, I haven't checked to see what Solaris does, but technically their UFS implementation does actually use separate inodes for their named streams, so stat(2) could return separate inode numbers for the named streams. (In fact, if you take a Solaris UFS filesystem with extended attributs, and run it on a Solaris 8 fsck, the directory containing named streams/extended attributes will show up in lost+found.) - Ted - 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/