Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751561Ab3GXOZp (ORCPT ); Wed, 24 Jul 2013 10:25:45 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:45793 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752364Ab3GXOGj (ORCPT ); Wed, 24 Jul 2013 10:06:39 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Jan Kara" , "Theodore Ts'o" Date: Wed, 24 Jul 2013 15:02:45 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [82/85] ext4: fix overflow when counting used blocks on 32-bit architectures In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.101 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1538 Lines: 47 3.2.49-rc1 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: Ben Hutchings --- fs/ext4/inode.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -4335,7 +4335,7 @@ 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); @@ -4352,7 +4352,7 @@ int ext4_getattr(struct vfsmount *mnt, s */ delalloc_blocks = 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; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/