From owner-freebsd-hackers@FreeBSD.ORG Sun Dec 1 22:05:33 2013 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 B834549F; Sun, 1 Dec 2013 22:05:33 +0000 (UTC) Received: from mail-pd0-x22f.google.com (mail-pd0-x22f.google.com [IPv6:2607:f8b0:400e:c02::22f]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 707BE1CA4; Sun, 1 Dec 2013 22:05:33 +0000 (UTC) Received: by mail-pd0-f175.google.com with SMTP id w10so16650439pde.6 for ; Sun, 01 Dec 2013 14:05:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=e1cv8YIMheI3OX3t9bbbaK+qTT2rZOgfN6/cxwukZW4=; b=uu6dUrTOgayKTn2DknVn8hnKtiPT74uDuotg4A1gTnNQEsMgL7j2tTrc9y+Py/DkUA MI2IHemiOb/7gnFpg64vRtvV4rggDXNaDpGdw3NRXmcwefP3khY8IKL7LIn8Rn8UWSEl 5/swyABTG4lJDxFFGTqLX+YHjnzkzkUI2d5I7eKmZEFUIIPKFqwzgDhcc1bdbqNDGxD8 7nidt3tPNdgC7JkfgD6WJ5PFNgkITz3UItLOb7NYAUOqz65KaurN39ICckhmd/XnfMz/ 44z0hstTvvJecUi90fHghFAfpX9HbvcpfM3jiSEdbmurUUus0GKMLp4S6N950IKRnq7d HoBA== MIME-Version: 1.0 X-Received: by 10.68.232.37 with SMTP id tl5mr27972344pbc.86.1385935532994; Sun, 01 Dec 2013 14:05:32 -0800 (PST) Received: by 10.70.64.132 with HTTP; Sun, 1 Dec 2013 14:05:32 -0800 (PST) In-Reply-To: <706707CA-BD52-4814-BCCE-EB044B062BA6@kientzle.com> References: <718836647.19911209.1385302696963.JavaMail.root@uoguelph.ca> <706707CA-BD52-4814-BCCE-EB044B062BA6@kientzle.com> Date: Sun, 1 Dec 2013 23:05:32 +0100 Message-ID: Subject: Re: O_XATTR support in FreeBSD? From: Lionel Cons To: Tim Kientzle Content-Type: text/plain; charset=ISO-8859-1 Cc: Rick Macklem , Cedric Blancher , Freebsd hackers list , Richard Yao , Pedro Giffuni , Jordan Hubbard X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.16 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 01 Dec 2013 22:05:33 -0000 On 27 November 2013 05:52, Tim Kientzle wrote: > > On Nov 26, 2013, at 1:51 AM, Cedric Blancher wrote: > >> 5. Support for tar and pax is already there. Its described in >> Solaris's fsattr man page, they use a extended header with filename >> /dev/null (to prevent older tar versions from tripping over the new >> headers) and then have a named attribute header which describes the >> attributes names and flags. > > There are quite a few alternative approaches for storing > extended attributes in tar and pax files. But this discussion is *not* about extended attributes, this discussion is about Alternate Data Streams. Unfortunately the O_XATTR discussion somehow started to cover the Linux "extended attribute system", which is utterly useless in the intended use cases (as said, no access through normal POSIX read(), write(), mmap(), no unlimited size, no sparse data support (aka SEEK_HOLE, SEEK_DATA) etc etc). Lionel