Date: Mon, 8 Sep 2014 19:16:20 -0400 (EDT) From: Rick Macklem <rmacklem@uoguelph.ca> To: John Baldwin <jhb@freebsd.org> Cc: freebsd-hackers@freebsd.org, Richard Yao <ryao@gentoo.org>, Lionel Cons <lionelcons1972@gmail.com>, Jan Bramkamp <crest@rlwinm.de> Subject: Re: Tool to access ZFS/NFSv4 alternate data streams on FreeBSD? Message-ID: <1152441008.33844915.1410218180664.JavaMail.root@uoguelph.ca> In-Reply-To: <2154953.PmiECqQQIi@ralph.baldwin.cx>
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John Baldwin wrote: > On Friday, September 05, 2014 06:13:10 PM Rick Macklem wrote: > > Lionel Cons wrote: > > > On 5 September 2014 19:26, Richard Yao <ryao@gentoo.org> 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. > Oh, just to clarify it, NFSv4 currently only supports resource forks and not EAs. Similar to NFSv4 ACLs, some believed EAs could be emulated via resource forks, but since modifying resource forks isn`t atomic, the ``NFSv4 collective`` has basically given up on that. There is a proposal to add EAs to NFSv4.n (where n is greater than 1), but I have no idea if or when this will exist. rick > -- > John Baldwin > _______________________________________________ > 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" >
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