"ext4_ext_put_in_cache" uses __u32 to receive physical block number
authorMingming Cao <cmm@us.ibm.com>
Tue, 31 Jul 2007 07:37:46 +0000 (00:37 -0700)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>
Tue, 31 Jul 2007 22:39:37 +0000 (15:39 -0700)
commitdd54567a83057821a667109a5cadec6eed0295de
tree88e06af13f4ba9db1fb61b2ebb5453e80ccd14c5
parent6676ae62822f189e7bca80526eca514c399adcfc
"ext4_ext_put_in_cache" uses __u32 to receive physical block number

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 <cmm@us.ibm.com>
Cc: Yan Zheng <yanzheng@21cn.com>
Cc: <stable@kernel.org>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/ext4/extents.c