From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965822Ab3GSF1R (ORCPT ); Fri, 19 Jul 2013 01:27:17 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:40007 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965761Ab3GSF1L (ORCPT ); Fri, 19 Jul 2013 01:27:11 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jan Kara , Theodore Tso Subject: [ 55/72] ext4: fix overflow when counting used blocks on 32-bit architectures Date: Thu, 18 Jul 2013 22:26:12 -0700 Message-Id: <20130719052603.616836136@linuxfoundation.org> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <20130719052559.852627424@linuxfoundation.org> References: <20130719052559.852627424@linuxfoundation.org> User-Agent: quilt/0.60-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jan Kara commit 8af8eecc1331dbf5e8c662022272cf667e213da5 upstream. The arithmetics adding delalloc blocks to the number of used blocks in ext4_getattr() can easily overflow on 32-bit archs as we first multiply number of blocks by blocksize and then divide back by 512. Make the arithmetics more clever and also use proper type (unsigned long long instead of unsigned long). Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/ext4/inode.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -4808,7 +4808,7 @@ int ext4_getattr(struct vfsmount *mnt, s struct kstat *stat) { struct inode *inode; - unsigned long delalloc_blocks; + unsigned long long delalloc_blocks; inode = dentry->d_inode; generic_fillattr(inode, stat); @@ -4826,7 +4826,7 @@ int ext4_getattr(struct vfsmount *mnt, s delalloc_blocks = EXT4_C2B(EXT4_SB(inode->i_sb), EXT4_I(inode)->i_reserved_data_blocks); - stat->blocks += (delalloc_blocks << inode->i_sb->s_blocksize_bits)>>9; + stat->blocks += delalloc_blocks << (inode->i_sb->s_blocksize_bits-9); return 0; }