Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756219AbcCOPih (ORCPT ); Tue, 15 Mar 2016 11:38:37 -0400 Received: from [198.137.202.9] ([198.137.202.9]:51860 "EHLO bombadil.infradead.org" rhost-flags-FAIL-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1754130AbcCOPie (ORCPT ); Tue, 15 Mar 2016 11:38:34 -0400 Date: Tue, 15 Mar 2016 08:37:44 -0700 From: Christoph Hellwig To: Richard Weinberger 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 Subject: Re: Page migration issue with UBIFS Message-ID: <20160315153744.GB28522@infradead.org> References: <56E8192B.5030008@nod.at> <20160315151727.GA16462@node.shutemov.name> <56E82B18.9040807@nod.at> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <56E82B18.9040807@nod.at> User-Agent: Mutt/1.5.24 (2015-08-30) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 480 Lines: 11 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.