Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762219AbXHQPko (ORCPT ); Fri, 17 Aug 2007 11:40:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756396AbXHQPkg (ORCPT ); Fri, 17 Aug 2007 11:40:36 -0400 Received: from turing-police.cc.vt.edu ([128.173.14.107]:39176 "EHLO turing-police.cc.vt.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756379AbXHQPkg (ORCPT ); Fri, 17 Aug 2007 11:40:36 -0400 X-Mailer: exmh version 2.7.2 01/07/2005 with nmh-1.2 To: Phillip Susi Cc: Kyle Moffett , Michael Tharp , alan , Marc Perkel , LKML Kernel , Lennart Sorensen , Al Viro Subject: Re: Thinking outside the box on file systems In-Reply-To: Your message of "Fri, 17 Aug 2007 11:19:21 EDT." <46C5BC79.9090204@cfl.rr.com> From: Valdis.Kletnieks@vt.edu References: <106259.96671.qm@web52501.mail.re2.yahoo.com> <46C2F96D.5030908@partiallystapled.com> <20070815133021.GB9412@csclub.uwaterloo.ca> <46C33934.7060802@cfl.rr.com> <46C3644C.9020102@cfl.rr.com> <87EEB1B3-7FFA-472C-B539-1A7AA2843869@mac.com> <46C37AD4.5060006@cfl.rr.com> <46C4689C.8020702@cfl.rr.com> <5D526964-3F46-4B6D-A12A-437A7EF5E0D8@mac.com> <46C5BC79.9090204@cfl.rr.com> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="==_Exmh_1187365183_3142P"; micalg=pgp-sha1; protocol="application/pgp-signature" Content-Transfer-Encoding: 7bit Date: Fri, 17 Aug 2007 11:39:43 -0400 Message-ID: <1942.1187365183@turing-police.cc.vt.edu> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1861 Lines: 48 --==_Exmh_1187365183_3142P Content-Type: text/plain; charset=us-ascii On Fri, 17 Aug 2007 11:19:21 EDT, Phillip Susi said: > Kyle Moffett wrote: >> Problem 1: "updating cached acls of descendent objects": How do you >> find out what a 'descendent object' is? Answer: You can't without >> recursing through the entire in-memory dentry tree. I suspect Kyle is not quite correct - it's probably the case that you don't have to consider just the in-memory dentries, but *all* the descendent objects in the entire file system. If you have a clever proof that on-disk can't *possibly* be affected, feel free to present it. (Does anybody know offhand what means 'chacl -r' uses to avoid race conditions with directories being moved in/out from under it, or does it just say "we'll make a best stab at it"?) > Yes, it would take some cpu time, and yes, it would have to use a lock > to protect the acl which would also lock out moves. Is that such a high > cost? Changing acls and moving whole directory trees around is not THAT > common of an operation... if it takes a wee bit more cpu time, I doubt > anyone will complain. It will become even *more* of a "not that common" if the lock will block moves and ACL changes *across the filesystem* for potentially *minutes* at a time. --==_Exmh_1187365183_3142P Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (GNU/Linux) Comment: Exmh version 2.5 07/13/2001 iD8DBQFGxcE/cC3lWbTT17ARAsQqAJ95p+iF5p9grk9NbN3jhnmflGKxRACbBFmj SBHIkRd2QSK2W5LqDV37lQk= =ZEl6 -----END PGP SIGNATURE----- --==_Exmh_1187365183_3142P-- - 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/