Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932878Ab1DZVfA (ORCPT ); Tue, 26 Apr 2011 17:35:00 -0400 Received: from mga14.intel.com ([143.182.124.37]:19974 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758746Ab1DZVN4 (ORCPT ); Tue, 26 Apr 2011 17:13:56 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.64,270,1301900400"; d="scan'208";a="425950992" From: Andi Kleen References: <20110426212.641772347@firstfloor.org> In-Reply-To: <20110426212.641772347@firstfloor.org> To: rgoldwyn@gmail.com, rgoldwyn@suse.de, jlbec@evilplan.org, gregkh@suse.de, ak@linux.intel.com, linux-kernel@vger.kernel.org, stable@kernel.org, tim.bird@am.sony.com Subject: [PATCH] [28/106] Treat writes as new when holes span across page boundaries Message-Id: <20110426211307.393173E1886@tassilo.jf.intel.com> Date: Tue, 26 Apr 2011 14:13:07 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1664 Lines: 44 2.6.35-longterm review patch. If anyone has any objections, please let me know. ------------------ From: Goldwyn Rodrigues commit 272b62c1f0f6f742046e45b50b6fec98860208a0 upstream. When a hole spans across page boundaries, the next write forces a read of the block. This could end up reading existing garbage data from the disk in ocfs2_map_page_blocks. This leads to non-zero holes. In order to avoid this, mark the writes as new when the holes span across page boundaries. Signed-off-by: Goldwyn Rodrigues Signed-off-by: jlbec Signed-off-by: Greg Kroah-Hartman Signed-off-by: Andi Kleen --- fs/ocfs2/aops.c | 6 ++++++ 1 file changed, 6 insertions(+) Index: linux-2.6.35.y/fs/ocfs2/aops.c =================================================================== --- linux-2.6.35.y.orig/fs/ocfs2/aops.c +++ linux-2.6.35.y/fs/ocfs2/aops.c @@ -1039,6 +1039,12 @@ static int ocfs2_prepare_page_for_write( ocfs2_figure_cluster_boundaries(OCFS2_SB(inode->i_sb), cpos, &cluster_start, &cluster_end); + /* treat the write as new if the a hole/lseek spanned across + * the page boundary. + */ + new = new | ((i_size_read(inode) <= page_offset(page)) && + (page_offset(page) <= user_pos)); + if (page == wc->w_target_page) { map_from = user_pos & (PAGE_CACHE_SIZE - 1); map_to = map_from + user_len; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/