From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753320AbaKLBVt (ORCPT ); Tue, 11 Nov 2014 20:21:49 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:58518 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753205AbaKLBVr (ORCPT ); Tue, 11 Nov 2014 20:21:47 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, hujianyang , Artem Bityutskiy Subject: [PATCH 3.17 049/319] UBIFS: fix free log space calculation Date: Wed, 12 Nov 2014 10:13:07 +0900 Message-Id: <20141112011000.684239839@linuxfoundation.org> X-Mailer: git-send-email 2.1.3 In-Reply-To: <20141112010952.553519040@linuxfoundation.org> References: <20141112010952.553519040@linuxfoundation.org> User-Agent: quilt/0.63-1 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.17-stable review patch. If anyone has any objections, please let me know. ------------------ From: Artem Bityutskiy commit ba29e721eb2df6df8f33c1f248388bb037a47914 upstream. Hu (hujianyang ) discovered an issue in the 'empty_log_bytes()' function, which calculates how many bytes are left in the log: " If 'c->lhead_lnum + 1 == c->ltail_lnum' and 'c->lhead_offs == c->leb_size', 'h' would equalent to 't' and 'empty_log_bytes()' would return 'c->log_bytes' instead of 0. " At this point it is not clear what would be the consequences of this, and whether this may lead to any problems, but this patch addresses the issue just in case. Tested-by: hujianyang Reported-by: hujianyang Signed-off-by: Artem Bityutskiy Signed-off-by: Greg Kroah-Hartman --- fs/ubifs/log.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/fs/ubifs/log.c +++ b/fs/ubifs/log.c @@ -106,10 +106,14 @@ static inline long long empty_log_bytes( h = (long long)c->lhead_lnum * c->leb_size + c->lhead_offs; t = (long long)c->ltail_lnum * c->leb_size; - if (h >= t) + if (h > t) return c->log_bytes - h + t; - else + else if (h != t) return t - h; + else if (c->lhead_lnum != c->ltail_lnum) + return 0; + else + return c->log_bytes; } /**