From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Yan Zheng" Subject: [BUG?] "ext4_ext_put_in_cache" uses __u32 to receive physical block number. Date: Fri, 27 Jul 2007 13:16:14 +0800 Message-ID: <3d0408630707262216i3f8e1c35ub49be9c210f963d8@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit To: linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org Return-path: Received: from nf-out-0910.google.com ([64.233.182.191]:18794 "EHLO nf-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753066AbXG0FQP (ORCPT ); Fri, 27 Jul 2007 01:16:15 -0400 Received: by nf-out-0910.google.com with SMTP id g13so46721nfb for ; Thu, 26 Jul 2007 22:16:14 -0700 (PDT) Content-Disposition: inline Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org Hi, all I think I found a bug in ext4/extents.c, "ext4_ext_put_in_cache" uses "__u32" to receive physical block number. "ext4_ext_put_in_cache" is used in "ext4_ext_get_blocks", it sets ext4 inode's extent cache according most recently tree lookup (higher 16 bits of saved physical block number are always zero). when serving a mapping request, "ext4_ext_get_blocks" first check whether the logical block is in inode's extent cache. if the logical block is in the cache and the cached region isn't a gap, "ext4_ext_get_blocks" gets physical block number by using cached region's physical block number and offset in the cached region. as described above, "ext4_ext_get_blocks" may return wrong result when there are physical block numbers bigger than 0xffffffff. Regards YZ