From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758478Ab1DMQEa (ORCPT ); Wed, 13 Apr 2011 12:04:30 -0400 Received: from kroah.org ([198.145.64.141]:54407 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758113Ab1DMPzh (ORCPT ); Wed, 13 Apr 2011 11:55:37 -0400 X-Mailbox-Line: From gregkh@clark.kroah.org Wed Apr 13 08:51:47 2011 Message-Id: <20110413155147.139187670@clark.kroah.org> User-Agent: quilt/0.48-16.4 Date: Wed, 13 Apr 2011 08:51:03 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Goldwyn Rodrigues , jlbec Subject: [39/74] Treat writes as new when holes span across page boundaries In-Reply-To: <20110413155406.GA22568@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.32-longterm 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;