Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933437AbdCJLu3 (ORCPT ); Fri, 10 Mar 2017 06:50:29 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:35960 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933066AbdCJJOH (ORCPT ); Fri, 10 Mar 2017 04:14:07 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Al Viro , Jan Kara , Theodore Tso Subject: [PATCH 4.4 47/91] ext4: fix data corruption in data=journal mode Date: Fri, 10 Mar 2017 10:08:46 +0100 Message-Id: <20170310083903.129027634@linuxfoundation.org> X-Mailer: git-send-email 2.12.0 In-Reply-To: <20170310083900.730556986@linuxfoundation.org> References: <20170310083900.730556986@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2440 Lines: 73 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jan Kara commit 3b136499e906460919f0d21a49db1aaccf0ae963 upstream. ext4_journalled_write_end() did not propely handle all the cases when generic_perform_write() did not copy all the data into the target page and could mark buffers with uninitialized contents as uptodate and dirty leading to possible data corruption (which would be quickly fixed by generic_perform_write() retrying the write but still). Fix the problem by carefully handling the case when the page that is written to is not uptodate. Reported-by: Al Viro Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/ext4/inode.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1220,7 +1220,9 @@ errout: * set the buffer to be dirty, since in data=journalled mode we need * to call ext4_handle_dirty_metadata() instead. */ -static void zero_new_buffers(struct page *page, unsigned from, unsigned to) +static void ext4_journalled_zero_new_buffers(handle_t *handle, + struct page *page, + unsigned from, unsigned to) { unsigned int block_start = 0, block_end; struct buffer_head *head, *bh; @@ -1237,7 +1239,7 @@ static void zero_new_buffers(struct page size = min(to, block_end) - start; zero_user(page, start, size); - set_buffer_uptodate(bh); + write_end_fn(handle, bh); } clear_buffer_new(bh); } @@ -1269,15 +1271,16 @@ static int ext4_journalled_write_end(str if (ext4_has_inline_data(inode)) copied = ext4_write_inline_data_end(inode, pos, len, copied, page); - else { - if (copied < len) { - if (!PageUptodate(page)) - copied = 0; - zero_new_buffers(page, from+copied, to); - } - + else if (unlikely(copied < len) && !PageUptodate(page)) { + copied = 0; + ext4_journalled_zero_new_buffers(handle, page, from, to); + } else { + if (unlikely(copied < len)) + ext4_journalled_zero_new_buffers(handle, page, + from + copied, to); ret = ext4_walk_page_buffers(handle, page_buffers(page), from, - to, &partial, write_end_fn); + from + copied, &partial, + write_end_fn); if (!partial) SetPageUptodate(page); }