From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Ross Subject: openg and path_to_handle Date: Wed, 06 Dec 2006 09:53:39 -0600 Message-ID: <4576E783.7020402@mcs.anl.gov> References: <6.2.3.4.2.20061127213243.04f786c0@cic-mail.lanl.gov> <20061128055428.GA29891@infradead.org> <20061129090450.GA16296@infradead.org> <20061129122313.GG14315@parisc-linux.org> <20061129123913.GA15994@infradead.org> <4570ACD1.7060800@mcs.anl.gov> <4574BF52.6090600@mcs.anl.gov> <20061206094805.GB33919298@melbourne.sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Latchesar Ionkov , Christoph Hellwig , Matthew Wilcox , Gary Grider , linux-fsdevel@vger.kernel.org Return-path: Received: from mailgw.mcs.anl.gov ([140.221.9.4]:36179 "EHLO mailgw.mcs.anl.gov" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935871AbWLFPxm (ORCPT ); Wed, 6 Dec 2006 10:53:42 -0500 To: David Chinner In-Reply-To: <20061206094805.GB33919298@melbourne.sgi.com> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org David Chinner wrote: > On Tue, Dec 05, 2006 at 05:47:16PM +0100, Latchesar Ionkov wrote: >> On 12/5/06, Rob Ross wrote: >>> Hi, >>> >>> I agree that it is not feasible to add new system calls every time >>> somebody has a problem, and we don't take adding system calls lightly. >>> However, in this case we're talking about an entire *community* of >>> people (high-end computing), not just one or two people. Of course it >>> may still be the case that that community is not important enough to >>> justify the addition of system calls; that's obviously not my call to make! >> I have the feeling that openg stuff is rushed without looking into all >> solutions, that don't require changes to the current interface. > > I also get the feeling that interfaces that already do this > open-by-handle stuff haven't been explored either. > > Does anyone here know about the XFS libhandle API? This has been > around for years and it does _exactly_ what these proposed syscalls > are supposed to do (and more). > > See: > > http://techpubs.sgi.com/library/tpl/cgi-bin/getdoc.cgi?coll=linux&db=man&fname=/usr/share/catman/man3/open_by_handle.3.html&srch=open_by_handle > > For the libhandle man page. Basically: > > openg == path_to_handle > sutoc == open_by_handle > > And here for the userspace code: > > http://oss.sgi.com/cgi-bin/cvsweb.cgi/xfs-cmds/xfsprogs/libhandle/ > > Cheers, > > Dave. Thanks for pointing these out Dave. These are indeed along the same lines as the openg()/openfh() approach. One difference is that they appear to perform permission checking on the open_by_handle(), which means that the entire path needs to be encoded in the handle, and makes it difficult to eliminate the path traversal overhead on N open_by_handle() operations. Regards, Rob