2007-07-29 07:00:04

by Andrew Morton

[permalink] [raw]
Subject: + ext4_ext_put_in_cache-uses-__u32-to-receive-physical.patch added to -mm tree

The patch titled
"ext4_ext_put_in_cache" uses __u32 to receive physical block number
has been added to the -mm tree. Its filename is

*** Remember to use Documentation/SubmitChecklist when testing your code ***

See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this

Subject: "ext4_ext_put_in_cache" uses __u32 to receive physical block number
From: Mingming Cao <[email protected]>

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 <[email protected]>
Cc: Yan Zheng <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

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);

Patches currently in -mm which might be from [email protected] are