From owner-freebsd-fs@FreeBSD.ORG Fri Jun 17 20:02:16 2005 Return-Path: X-Original-To: freebsd-fs@freebsd.org Delivered-To: freebsd-fs@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2F9FF16A537; Fri, 17 Jun 2005 20:02:16 +0000 (GMT) (envelope-from ezk@fsl.cs.sunysb.edu) Received: from filer.fsl.cs.sunysb.edu (filer.fsl.cs.sunysb.edu [130.245.126.2]) by mx1.FreeBSD.org (Postfix) with ESMTP id DE1D243D4C; Fri, 17 Jun 2005 20:02:15 +0000 (GMT) (envelope-from ezk@fsl.cs.sunysb.edu) Received: from agora.fsl.cs.sunysb.edu (agora.fsl.cs.sunysb.edu [130.245.126.12]) by filer.fsl.cs.sunysb.edu (8.12.8/8.12.8) with ESMTP id j5HK2C3T004706; Fri, 17 Jun 2005 16:02:12 -0400 Received: from agora.fsl.cs.sunysb.edu (localhost.localdomain [127.0.0.1]) by agora.fsl.cs.sunysb.edu (8.13.1/8.13.1) with ESMTP id j5HK2B59016369; Fri, 17 Jun 2005 16:02:11 -0400 Received: (from ezk@localhost) by agora.fsl.cs.sunysb.edu (8.13.1/8.12.8/Submit) id j5HK2AVS016366; Fri, 17 Jun 2005 16:02:10 -0400 Date: Fri, 17 Jun 2005 16:02:10 -0400 Message-Id: <200506172002.j5HK2AVS016366@agora.fsl.cs.sunysb.edu> From: Erez Zadok To: Allan Fields In-reply-to: Your message of "Thu, 16 Jun 2005 22:08:03 EDT." <20050617020803.GC95979@afields.ca> X-MailKey: Erez_Zadok Cc: freebsd-fs@freebsd.org, jwd@freebsd.org Subject: Re: Summer of Code: Magic Links, FiST/vnode stacking?, ReiserFS X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 17 Jun 2005 20:02:16 -0000 In message <20050617020803.GC95979@afields.ca>, Allan Fields writes: > * FiST / vnode stacking (Coordinating w/ Erez Zadok?): > > This is one I wanted to see move forward on *BSD. What FiST offers > is a unified approach for template file systems which can aid in > cross-platform development of filesystem code (potentially) saving > a significant amount of developer effort and duplication. It's > been around for a number of years now and FreeBSD templates do > exist. Good timing: we just released fistgen-0.1.2, which contains updated ports to FreeBSD-5.x. You may get it from ftp://ftp.filesystems.org/pub/fist/fistgen-0.1.2.tar.gz > The Size-Changing Algorithm (SCA) code is Linux specific, > so I'm not certain of the status. The SCA code is indeed only in the Linux templates and hasn't been ported to the FreeBSD ones. There are also several SCA-related bugs in our bugzilla server, yet to be fixed. > Areas left to address: FreeBSD Templates (remaining build issues, > keep templates up to date, etc.), SCA: Size-Changing-Algorithm (some > work on this internally w/ the Stony Brook team?), Our group would love to work with anyone in the freebsd community to get more and stable stackable file systems into freebsd. > Cache Coherency issues, etc. Cache coherency has always been an issue with stackable file systems. What OSs need is something like Heindeman did in his SOSP 1995 paper. > [http://www.fsl.cs.sunysb.edu , http://www.filesystems.org ] > > Desirable/Related File System Ports: ncryptfs and/or ecryptfs, > gzipfs, unionfs [ne]cryptfs would indeed be very nice to have, but I thought that freebsd already had some pretty powerful crypto device-level support, no? gzipfs will "just work" once the SCA code is ported to freebsd. Unionfs is another story. We've developed and released a unioning f/s for Linux, and in the 6+ months since it's been released, we've had many downloads and users -- and consequenetly many bugs reported and mostly fixed. We've found out that doing namespace unification properly (i.e., unix semeantics compliant) is much harder than it initially seems. We've written a detailed tech report on it. If anyone is going to tackle fixing the freebsd unionfs, you should read our tech-report first. Cheers, Erez.