From owner-freebsd-hackers@FreeBSD.ORG Mon Sep 8 17:09:08 2014 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id CF79DDB2 for ; Mon, 8 Sep 2014 17:09:08 +0000 (UTC) Received: from bigwig.baldwin.cx (bigwig.baldwin.cx [IPv6:2001:470:1f11:75::1]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id A6C041BD7 for ; Mon, 8 Sep 2014 17:09:08 +0000 (UTC) Received: from ralph.baldwin.cx (pool-173-70-85-31.nwrknj.fios.verizon.net [173.70.85.31]) by bigwig.baldwin.cx (Postfix) with ESMTPSA id 1F192B923; Mon, 8 Sep 2014 13:09:07 -0400 (EDT) From: John Baldwin To: freebsd-hackers@freebsd.org Subject: Re: Tool to access ZFS/NFSv4 alternate data streams on FreeBSD? Date: Mon, 08 Sep 2014 11:55:13 -0400 Message-ID: <2154953.PmiECqQQIi@ralph.baldwin.cx> User-Agent: KMail/4.10.5 (FreeBSD/10.0-STABLE; KDE/4.10.5; amd64; ; ) In-Reply-To: <1538621043.33014113.1409955190712.JavaMail.root@uoguelph.ca> References: <1538621043.33014113.1409955190712.JavaMail.root@uoguelph.ca> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.2.7 (bigwig.baldwin.cx); Mon, 08 Sep 2014 13:09:07 -0400 (EDT) Cc: Richard Yao , Rick Macklem , Lionel Cons , Jan Bramkamp X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 08 Sep 2014 17:09:08 -0000 On Friday, September 05, 2014 06:13:10 PM Rick Macklem wrote: > Lionel Cons wrote: > > On 5 September 2014 19:26, Richard Yao wrote: > > > On 09/05/2014 11:35 AM, Jan Bramkamp wrote: > > >> On 05.09.2014 16:25, Lionel Cons wrote:> Is there any tool which > > >> can be > > >> used to access ZFS and NFSv4 alternate > > >> > > >>> data streams on FreeBSD? > > >> > > >> Are you looking for lsextattr(8) and getextattr(8)? > > >> _______________________________________________ > > >> freebsd-hackers@freebsd.org mailing list > > >> http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > > >> To unsubscribe, send any mail to > > >> "freebsd-hackers-unsubscribe@freebsd.org" > > > > > > Do you mean Solaris extended attributes? Those tend to be called > > > resource forks on other platforms. Unifying extended attributes and > > > resource forks was clever. > > > > Yes, they are also called resource forks, or alternate data streams. > > The attribute files which can be accessed via O_XATTR or cd -@ > > file/dir on newer ksh/ksh93/bash revisions. > > For FreeBSD's NFSv4 the answer is definitely no. Because the Linux/FreeBSD > style setextattr() assumes an atomic replacement of the extended attribute, > it is not semantically compatible (ie. cannot be accurately emulated) by > resource forks. > > I do not know of any work for ZFS on FreeBSD w.r.t. this, but I'm not a > ZFS guy. Does the NFSv4 protocol support resource forks as a separate entity from EAs though? Presumably O_XATTR would turn into a new VOP (VOP_OPENFORK() or some such), it wouldn't be shoehorned into the EA APIs. -- John Baldwin