From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758307Ab2CMASj (ORCPT ); Mon, 12 Mar 2012 20:18:39 -0400 Received: from mail.windriver.com ([147.11.1.11]:46916 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757664Ab2CMASe (ORCPT ); Mon, 12 Mar 2012 20:18:34 -0400 From: Paul Gortmaker To: stable@kernel.org, linux-kernel@vger.kernel.org Cc: stable-review@kernel.org, Goldwyn Rodrigues , Goldwyn Rodrigues , jlbec , Paul Gortmaker Subject: [34-longterm 038/196] Treat writes as new when holes span across page boundaries Date: Mon, 12 Mar 2012 20:12:46 -0400 Message-Id: <1331597724-31358-39-git-send-email-paul.gortmaker@windriver.com> X-Mailer: git-send-email 1.7.9.3 In-Reply-To: <1331597724-31358-1-git-send-email-paul.gortmaker@windriver.com> References: <1331597724-31358-1-git-send-email-paul.gortmaker@windriver.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Goldwyn Rodrigues ------------------- This is a commit scheduled for the next v2.6.34 longterm release. If you see a problem with using this for longterm, please comment. ------------------- 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: Paul Gortmaker --- fs/ocfs2/aops.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c index e504ab7..3de08db 100644 --- a/fs/ocfs2/aops.c +++ b/fs/ocfs2/aops.c @@ -1035,6 +1035,12 @@ static int ocfs2_prepare_page_for_write(struct inode *inode, u64 *p_blkno, 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; -- 1.7.9.3