From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id q7N55GSc136155 for ; Thu, 23 Aug 2012 00:05:16 -0500 Received: from ipmail04.adl6.internode.on.net (ipmail04.adl6.internode.on.net [150.101.137.141]) by cuda.sgi.com with ESMTP id IIBdMYUSmBGqaEl3 for ; Wed, 22 Aug 2012 22:06:02 -0700 (PDT) Received: from disappointment ([192.168.1.1]) by dastard with esmtp (Exim 4.76) (envelope-from ) id 1T4Pc9-0003Kq-LJ for xfs@oss.sgi.com; Thu, 23 Aug 2012 15:05:53 +1000 Received: from dave by disappointment with local (Exim 4.80) (envelope-from ) id 1T4Pc9-0003jr-Hf for xfs@oss.sgi.com; Thu, 23 Aug 2012 15:05:53 +1000 From: Dave Chinner Subject: [PATCH 102/102] xfs: handle EOF correctly in xfs_vm_writepage Date: Thu, 23 Aug 2012 15:03:00 +1000 Message-Id: <1345698180-13612-103-git-send-email-david@fromorbit.com> In-Reply-To: <1345698180-13612-1-git-send-email-david@fromorbit.com> References: <1345698180-13612-1-git-send-email-david@fromorbit.com> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: xfs@oss.sgi.com From: Christoph Hellwig Upstream commit: 6b7a03f03a2f8b1629133e35729eba4727fae3cc We need to zero out part of a page which beyond EOF before setting uptodate, otherwise, mapread or write will see non-zero data beyond EOF. Based on the code in fs/buffer.c and the following ext4 commit: ext4: handle EOF correctly in ext4_bio_write_page() And yes, I wish we had a good test case for it. Signed-off-by: Christoph Hellwig Reviewed-by: Mark Tinguely Signed-off-by: Ben Myers --- fs/xfs/linux-2.6/xfs_aops.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c index 42eaf00..8c2ed74 100644 --- a/fs/xfs/linux-2.6/xfs_aops.c +++ b/fs/xfs/linux-2.6/xfs_aops.c @@ -978,11 +978,26 @@ xfs_vm_writepage( end_index = offset >> PAGE_CACHE_SHIFT; last_index = (offset - 1) >> PAGE_CACHE_SHIFT; if (page->index >= end_index) { - if ((page->index >= end_index + 1) || - !(i_size_read(inode) & (PAGE_CACHE_SIZE - 1))) { + unsigned offset_into_page = offset & (PAGE_CACHE_SIZE - 1); + + /* + * Just skip the page if it is fully outside i_size, e.g. due + * to a truncate operation that is in progress. + */ + if (page->index >= end_index + 1 || offset_into_page == 0) { unlock_page(page); return 0; } + + /* + * The page straddles i_size. It must be zeroed out on each + * and every writepage invocation because it may be mmapped. + * "A file is mapped in multiples of the page size. For a file + * that is not a multiple of the page size, the remaining + * memory is zeroed when mapped, and writes to that region are + * not written out to the file." + */ + zero_user_segment(page, offset_into_page, PAGE_CACHE_SIZE); } end_offset = min_t(unsigned long long, -- 1.7.10 _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs