Do not use BLOCK_SIZE.
It's already used by the kernel; replace by YAFFS_BLOCK_SIZE.
diff --git a/fs/yaffs2/yaffs_ramem.c b/fs/yaffs2/yaffs_ramem.c
--- a/fs/yaffs2/yaffs_ramem.c
+++ b/fs/yaffs2/yaffs_ramem.c
@@ -35,10 +35,10 @@ const char *yaffs_ramem_c_version = "$Id
#define EM_SIZE_IN_MEG 2
-#define BLOCK_SIZE (32 * 528)
+#define YAFFS_BLOCK_SIZE (32 * 528)
#define BLOCKS_PER_MEG ((1024*1024)/(32 * 512))
#define FILE_SIZE_IN_BLOCKS (FILE_SIZE_IN_MEG * BLOCKS_PER_MEG)
-#define FILE_SIZE_IN_BYTES (FILE_SIZE_IN_BLOCKS * BLOCK_SIZE)
+#define FILE_SIZE_IN_BYTES (FILE_SIZE_IN_BLOCKS * YAFFS_BLOCK_SIZE)