Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964828AbcCOXS6 (ORCPT ); Tue, 15 Mar 2016 19:18:58 -0400 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 S1751906AbcCOXS4 (ORCPT ); Tue, 15 Mar 2016 19:18:56 -0400 Subject: Re: Page migration issue with UBIFS To: Christoph Hellwig References: <56E8192B.5030008@nod.at> <20160315151727.GA16462@node.shutemov.name> <56E82B18.9040807@nod.at> <20160315153744.GB28522@infradead.org> Cc: "Kirill A. Shutemov" , linux-fsdevel , "linux-mtd@lists.infradead.org" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Boris Brezillon , Maxime Ripard , David Gstir , Dave Chinner , Artem Bityutskiy , "Kirill A. Shutemov" , Alexander Kaplan From: Richard Weinberger Message-ID: <56E8985A.1020509@nod.at> Date: Wed, 16 Mar 2016 00:18:50 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.4.0 MIME-Version: 1.0 In-Reply-To: <20160315153744.GB28522@infradead.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 720 Lines: 19 Am 15.03.2016 um 16:37 schrieb Christoph Hellwig: > On Tue, Mar 15, 2016 at 04:32:40PM +0100, Richard Weinberger wrote: >>> Or if ->page_mkwrite() was called, why the page is not dirty? >> >> BTW: UBIFS does not implement ->migratepage(), could this be a problem? > > This might be the reason. I can't reall make sense of > buffer_migrate_page, but it seems to migrate buffer_head state to > the new page. > > I'd love to know why CMA even tries to migrate pages that don't have a > ->migratepage method, this seems incredibly dangerous to me. FYI, with a dummy ->migratepage() which returns only -EINVAL UBIFS does no longer explode upon page migration. Tomorrow I'll do more tests to make sure. Thanks, //richard