Return-Path: Received: from a.ns.miles-group.at ([95.130.255.143]:11949 "EHLO radon.swed.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932841AbcEKOJj (ORCPT ); Wed, 11 May 2016 10:09:39 -0400 Subject: Re: Reconsidering exportable UBIFS To: NeilBrown , Al Viro References: <5702E7F5.1050807@nod.at> <871t5curbl.fsf@notabene.neil.brown.name> <20160508232533.GH2694@ZenIV.linux.org.uk> <87y47ju8kk.fsf@notabene.neil.brown.name> Cc: linux-fsdevel , "linux-mtd@lists.infradead.org" , Artem Bityutskiy , Christoph Hellwig , NFS List From: Richard Weinberger Message-ID: <57333D1E.9090706@nod.at> Date: Wed, 11 May 2016 16:09:34 +0200 MIME-Version: 1.0 In-Reply-To: <87y47ju8kk.fsf@notabene.neil.brown.name> Content-Type: text/plain; charset=US-ASCII Sender: linux-nfs-owner@vger.kernel.org List-ID: Am 09.05.2016 um 07:03 schrieb NeilBrown: > On Mon, May 09 2016, Al Viro wrote: > >> On Mon, May 09, 2016 at 08:18:22AM +1000, NeilBrown wrote: >> >>> Not puppies, just kittens. >>> >>> If you don't provide these functions, then exporting with >>> "subtree_check" won't work. That is no great loss except that people >>> might find the failure confusing. >> >> OK, a client sends you a RENAME. With fhandles of both parents + >> old and new names in those. Your task, should you choose to accept it, is >> to figure out whether we should fail with nfserr_inval due to an attempt >> to make a directory its own descendent. Without being able to locate all >> ancestors of a directory. > > You are right, sorry. I was thinking that get_parent() was for finding > the parent of a non-directory, but it is for directories. It does the > equivalent of lookup(".."). So if you have a ".." link or something > like it, it should be easy. If you don't, it won't be easy at all. Thanks for the detailed explanation. UBIFS does not have ".." links in the on-flash layout. So, we'd have to change this. Thanks, //richard