diff --git a/fs/ntfs3/index.c b/fs/ntfs3/index.c
index 6aa9540ece4728b5a02108924db76b4ee920a353..9386c551e208204870363685b27826ccb60e1171 100644
--- a/fs/ntfs3/index.c
+++ b/fs/ntfs3/index.c
@@ -2012,7 +2012,7 @@ static int indx_shrink(struct ntfs_index *indx, struct ntfs_inode *ni,
 		unsigned long pos;
 		const unsigned long *bm = resident_data(b);
 
-		nbits = le32_to_cpu(b->res.data_size) * 8;
+		nbits = (size_t)le32_to_cpu(b->res.data_size) * 8;
 
 		if (bit >= nbits)
 			return 0;