[PATCH] BLOCK: Move extern declarations out of fs/*.c into header files [try #6]

Create a new header file, fs/internal.h, for common definitions local to the
sources in the fs/ directory.

Move extern definitions that should be in header files from fs/*.c to
fs/internal.h or other main header files where they span directories.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 892643d..0639024 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -22,8 +22,7 @@
 #include <linux/blkdev.h>
 #include <linux/backing-dev.h>
 #include <linux/buffer_head.h>
-
-extern struct super_block *blockdev_superblock;
+#include "internal.h"
 
 /**
  *	__mark_inode_dirty -	internal function