Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966758AbcCPOWD (ORCPT ); Wed, 16 Mar 2016 10:22:03 -0400 Received: from mail-wm0-f50.google.com ([74.125.82.50]:36912 "EHLO mail-wm0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966561AbcCPOWA (ORCPT ); Wed, 16 Mar 2016 10:22:00 -0400 Date: Wed, 16 Mar 2016 17:21:56 +0300 From: "Kirill A. Shutemov" To: Richard Weinberger Cc: Christoph Hellwig , 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: <20160316142156.GA23595@node.shutemov.name> References: <56E8192B.5030008@nod.at> <20160315151727.GA16462@node.shutemov.name> <56E82B18.9040807@nod.at> <20160315153744.GB28522@infradead.org> <56E8985A.1020509@nod.at> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <56E8985A.1020509@nod.at> User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2089 Lines: 64 On Wed, Mar 16, 2016 at 12:18:50AM +0100, Richard Weinberger wrote: > 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. Could you check if something like this would fix the issue. Completely untested. diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c index 065c88f8e4b8..9da34120dc5e 100644 --- a/fs/ubifs/file.c +++ b/fs/ubifs/file.c @@ -52,6 +52,7 @@ #include "ubifs.h" #include #include +#include static int read_block(struct inode *inode, void *addr, unsigned int block, struct ubifs_data_node *dn) @@ -1452,6 +1453,20 @@ static int ubifs_set_page_dirty(struct page *page) return ret; } +static int ubifs_migrate_page(struct address_space *mapping, + struct page *newpage, struct page *page, enum migrate_mode mode) +{ + if (PagePrivate(page)) { + SetPagePrivate(newpage); + __set_page_dirty_nobuffers(newpage); + } + + if (PageChecked(page)) + SetPageChecked(newpage); + + return migrate_page(mapping, newpage, page, mode); +} + static int ubifs_releasepage(struct page *page, gfp_t unused_gfp_flags) { /* @@ -1591,6 +1606,7 @@ const struct address_space_operations ubifs_file_address_operations = { .write_end = ubifs_write_end, .invalidatepage = ubifs_invalidatepage, .set_page_dirty = ubifs_set_page_dirty, + .migratepage = ubifs_migrate_page, .releasepage = ubifs_releasepage, }; -- Kirill A. Shutemov