[2.6.20.17 review 26/58] "ext4_ext_put_in_cache" uses __u32 to receive physical block number

Willy Tarreau
2007-08-22T09:06:41Z

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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: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
fs/ext4/extents.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index dc2724f..14b0b49 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -1397,7 +1397,7 @@ int ext4_ext_walk_space(struct inode *inode, unsigned long block,

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);
--
1.5.2.5

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