From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932663Ab1DYUj6 (ORCPT ); Mon, 25 Apr 2011 16:39:58 -0400 Received: from 1wt.eu ([62.212.114.60]:34406 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932326Ab1DYUY6 (ORCPT ); Mon, 25 Apr 2011 16:24:58 -0400 Message-Id: <20110425200238.902101275@pcw.home.local> User-Agent: quilt/0.48-1 Date: Mon, 25 Apr 2011 22:04:48 +0200 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@kernel.org, stable-review@kernel.org Cc: Goldwyn Rodrigues , jlbec , Greg Kroah-Hartman Subject: [PATCH 136/173] Treat writes as new when holes span across page boundaries In-Reply-To: <46075c3a3ef08be6d70339617d6afc98@local> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.27.59-stable review patch. If anyone has any objections, please let us 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 --- fs/ocfs2/aops.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/fs/ocfs2/aops.c +++ b/fs/ocfs2/aops.c @@ -1091,6 +1091,12 @@ 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;