From: Mingming Cao Subject: Re: [BUG?] "ext4_ext_put_in_cache" uses __u32 to receive physical block number. Date: Fri, 27 Jul 2007 08:39:43 -0700 Message-ID: <1185550783.6656.4.camel@localhost.localdomain> References: <3d0408630707262216i3f8e1c35ub49be9c210f963d8@mail.gmail.com> Reply-To: cmm@us.ibm.com Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org To: Yan Zheng , akpm@osdl.org, stable@kernel.org, tytso@mit.edu Return-path: Received: from e35.co.us.ibm.com ([32.97.110.153]:38449 "EHLO e35.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756854AbXG0Pjt (ORCPT ); Fri, 27 Jul 2007 11:39:49 -0400 In-Reply-To: <3d0408630707262216i3f8e1c35ub49be9c210f963d8@mail.gmail.com> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Fri, 2007-07-27 at 13:16 +0800, Yan Zheng wrote: > 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 You are right. Thanks for reporting this! Signed-off-by: Mingming Cao Index: linux-2.6.22/fs/ext4/extents.c =================================================================== --- linux-2.6.22.orig/fs/ext4/extents.c 2007-07-27 08:31:02.000000000 -0700 +++ linux-2.6.22/fs/ext4/extents.c 2007-07-27 08:31:48.000000000 -0700 @@ -1544,7 +1544,7 @@ int ext4_ext_walk_space(struct inode *in static void ext4_ext_put_in_cache(struct inode *inode, __u32 block, - __u32 len, __u32 start, int type) + __u32 len, ext4_fsblk_t start, int type) { struct ext4_ext_cache *cex; BUG_ON(len == 0);