[2.6.22.2 review 43/84] "ext4_ext_put_in_cache" uses __u32 toreceive physical block number

[Greg KH]

From: Mingming Cao <cmm@xxxxxxxxxx>

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@xxxxxxxxxx>
Cc: Yan Zheng <yanzheng@xxxxxxxx>
Cc: <linux-ext4@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 fs/ext4/extents.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -1445,7 +1445,7 @@ 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);

-- 
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