[PATCH] udf: Fix i_lenExtents truncation on 32-bit kernels

[Zhan Xusheng]

In udf_do_extend_file() the total extent length is rounded up to a block
boundary with:

	iinfo->i_lenExtents = (iinfo->i_lenExtents + sb->s_blocksize - 1) &
			      ~(sb->s_blocksize - 1);

i_lenExtents is a __u64, but sb->s_blocksize is unsigned long.  On 32-bit
kernels unsigned long is 32-bit, so ~(sb->s_blocksize - 1) is a 32-bit
value (e.g. 0xfffff800 for a 2 KiB block) that is zero-extended in the AND,
clearing the upper 32 bits of i_lenExtents.  For UDF files whose total
extent length exceeds 4 GiB this truncates i_lenExtents when the file is
extended, corrupting the tracked extent length.

Cast the block size to 64-bit before forming the mask.  64-bit kernels are
unaffected.

Fixes: 48d6d8ff7dca ("udf: cache struct udf_inode_info")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Zhan Xusheng <zhanxusheng@xxxxxxxxxx>
---
 fs/udf/inode.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index 67bcf83758c8..c519644acfd7 100644
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -531,7 +531,7 @@ static int udf_do_extend_file(struct inode *inode,
 			  sb->s_blocksize - 1) & ~(sb->s_blocksize - 1));
 		iinfo->i_lenExtents =
 			(iinfo->i_lenExtents + sb->s_blocksize - 1) &
-			~(sb->s_blocksize - 1);
+			~((u64)sb->s_blocksize - 1);
 	}
 
 	add = 0;
-- 
2.43.0