From: akpm@linux-foundation.org Subject: [patch 023/109] "ext4_ext_put_in_cache" uses __u32 to receive physical block number Date: Tue, 31 Jul 2007 00:37:46 -0700 Message-ID: <200707310737.l6V7bk50021902@imap1.linux-foundation.org> Cc: akpm@linux-foundation.org, cmm@us.ibm.com, linux-ext4@vger.kernel.org, stable@kernel.org, yanzheng@21cn.com To: torvalds@linux-foundation.org Return-path: Received: from smtp2.linux-foundation.org ([207.189.120.14]:39493 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751894AbXGaHsH (ORCPT ); Tue, 31 Jul 2007 03:48:07 -0400 Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org From: Mingming Cao Yan Zheng wrote: > 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. > You are right. Thanks for reporting this! Signed-off-by: Mingming Cao Cc: Yan Zheng Cc: Cc: Signed-off-by: Andrew Morton --- fs/ext4/extents.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff -puN fs/ext4/extents.c~ext4_ext_put_in_cache-uses-__u32-to-receive-physical fs/ext4/extents.c --- a/fs/ext4/extents.c~ext4_ext_put_in_cache-uses-__u32-to-receive-physical +++ a/fs/ext4/extents.c @@ -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); _