From owner-freebsd-hackers@FreeBSD.ORG Sat Nov 23 22:53:47 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 EE8ED5F1; Sat, 23 Nov 2013 22:53:47 +0000 (UTC) Received: from esa-annu.net.uoguelph.ca (esa-annu.mail.uoguelph.ca [131.104.91.36]) by mx1.freebsd.org (Postfix) with ESMTP id A3EED2007; Sat, 23 Nov 2013 22:53:46 +0000 (UTC) X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AqQEAMcxkVKDaFve/2dsb2JhbABZgz9Tgnm4Vk6BMnSCJQEBAQMBAQEBICsgCwUWDgoCAg0ZAikBCSYGCAcEARwBA4daBg2uCZBCF4EpjQYHAQEbNAeCa4FIA4lCjAODf4kbh0eDRh4xewkXIg X-IronPort-AV: E=Sophos;i="4.93,759,1378872000"; d="scan'208";a="71626984" Received: from muskoka.cs.uoguelph.ca (HELO zcs3.mail.uoguelph.ca) ([131.104.91.222]) by esa-annu.net.uoguelph.ca with ESMTP; 23 Nov 2013 17:53:38 -0500 Received: from zcs3.mail.uoguelph.ca (localhost.localdomain [127.0.0.1]) by zcs3.mail.uoguelph.ca (Postfix) with ESMTP id 04940B40EB; Sat, 23 Nov 2013 17:53:38 -0500 (EST) Date: Sat, 23 Nov 2013 17:53:38 -0500 (EST) From: Rick Macklem To: Pedro Giffuni Message-ID: <820263347.19772534.1385247218007.JavaMail.root@uoguelph.ca> In-Reply-To: <5290B60D.2050006@FreeBSD.org> Subject: Re: O_XATTR support in FreeBSD? MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [172.17.91.203] X-Mailer: Zimbra 7.2.1_GA_2790 (ZimbraWebClient - FF3.0 (Win)/7.2.1_GA_2790) Cc: Freebsd hackers list , Richard Yao , Cedric Blancher 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: Sat, 23 Nov 2013 22:53:48 -0000 Pedro Giffuni wrote: > On 23.11.2013 02:13, Cedric Blancher wrote: > > On 22 November 2013 20:55, Pedro Giffuni wrote: > >> Well ... > >> > >> According to: > >> > >> https://wiki.freebsd.org/ZFS > >> > >> We do support Extended Attributes on ZFS but they differ from the > >> ones in > >> Solaris (and Linux). > > Well, we need the one specified in the NFSv4 standard. The Linux > > extended attributes are pretty much useless because they are size > > restricted (typical attribute size here is in the GB range, and for > > example NIH and CERN have even much bigger sizes), can't be > > accessed > > like normal files and are incompatible to Window's Alternate > > Streams. > > > > Ced > > I was unaware of a standard for EA beyond the old posix draft. > The reason for Extended Attributes is supporting ACL and we support > both > the draft posix and the NFS/win style ACLs. > Interestingly, FreeBSD has a VOP_OPENEXTATTR() but no syscall that uses it nor support for it in ZFS. (I'm just guessing it was intended for an openat(2) syscall at some time?) Btw Cedric, if you had mentioned "subfiles" or "fork files" in your subject line, you might have gotten a better answer. I, for one, didn't know what O_XATTR is. I also always get confused w.r.t. what to call these beasts. (NFSv4 calls the named attributes.) Btw, apps can use extended attributes (the limited sized atomically stored/read kind). They aren't just for storing ACLs. > Not sure about the status of NFSv4. The guys in the posix-1e list > should > know better. > The NFSv4 implementation in FreeBSD does not support it, although adding it wouldn't be hard if someone figures out how to do the syscall and adds support for the VOP()s in ZFS. (I'm not volunteering to do the latter. I have plenty of other stuff on my to-do list;-) rick > regards, > > Pedro. > _______________________________________________ > 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" >