From patchwork Mon Jul 21 21:21:33 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamal Mostafa X-Patchwork-Id: 372215 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 1823A140143; Tue, 22 Jul 2014 07:22:06 +1000 (EST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1X9L23-0000gW-3A; Mon, 21 Jul 2014 21:22:03 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1X9L1c-0000Md-G2 for kernel-team@lists.ubuntu.com; Mon, 21 Jul 2014 21:21:36 +0000 Received: from c-67-160-228-185.hsd1.ca.comcast.net ([67.160.228.185] helo=fourier) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1X9L1b-0007IT-Bv; Mon, 21 Jul 2014 21:21:35 +0000 Received: from kamal by fourier with local (Exim 4.82) (envelope-from ) id 1X9L1Z-0000EK-DZ; Mon, 21 Jul 2014 14:21:33 -0700 From: Kamal Mostafa To: Jan Kara Subject: [3.8.y.z extended stable] Patch "ext4: fix zeroing of page during writeback" has been added to staging queue Date: Mon, 21 Jul 2014 14:21:33 -0700 Message-Id: <1405977693-846-1-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 X-Extended-Stable: 3.8 Cc: Xiaoguang Wang , Kamal Mostafa , Theodore Ts'o , kernel-team@lists.ubuntu.com X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com This is a note to let you know that I have just added a patch titled ext4: fix zeroing of page during writeback to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue This patch is scheduled to be released in version 3.8.13.27. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.8.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From 7c4c750c432da0d9f026b4af0641843a69c3b1e4 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Tue, 27 May 2014 12:48:55 -0400 Subject: ext4: fix zeroing of page during writeback commit eeece469dedadf3918bad50ad80f4616a0064e90 upstream. Tail of a page straddling inode size must be zeroed when being written out due to POSIX requirement that modifications of mmaped page beyond inode size must not be written to the file. ext4_bio_write_page() did this only for blocks fully beyond inode size but didn't properly zero blocks partially beyond inode size. Fix this. The problem has been uncovered by mmap_11-4 test in openposix test suite (part of LTP). Reported-by: Xiaoguang Wang Fixes: 5a0dc7365c240 Fixes: bd2d0210cf22f Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o Signed-off-by: Kamal Mostafa --- fs/ext4/page-io.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) -- 1.9.1 diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c index 311d1db..a30ef89 100644 --- a/fs/ext4/page-io.c +++ b/fs/ext4/page-io.c @@ -446,24 +446,24 @@ int ext4_bio_write_page(struct ext4_io_submit *io, set_page_writeback(page); ClearPageError(page); + /* + * Comments copied from block_write_full_page_endio: + * + * 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." + */ + if (len < PAGE_CACHE_SIZE) + zero_user_segment(page, len, PAGE_CACHE_SIZE); + for (bh = head = page_buffers(page), block_start = 0; bh != head || !block_start; block_start = block_end, bh = bh->b_this_page) { block_end = block_start + blocksize; if (block_start >= len) { - /* - * Comments copied from block_write_full_page_endio: - * - * 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, block_start, block_end); clear_buffer_dirty(bh); set_buffer_uptodate(bh); continue;