[PATCH] include buffer_head.h in actual users instead of fs.h (1/10)

Now that fs.h grow due to the lock.h removal let's reduce it's overhead
again:  Instead of penalizing ever user of fs.h with the overhead of the
buffer head interface let it's users include it directly.

This also shows nicely which parts of the core kernel still depend on the
buffer head interface, and allows that to be cleaned up properly.

This is the first of ten patches and adds the includes needed by
buffer_head.h to it and fixes it's inclusion guard.

include/linux/buffer_head.h

@@ -4,8 +4,13 @@
  * Everything to do with buffer_heads.
  */
 
-#ifndef BUFFER_FLAGS_H
-#define BUFFER_FLAGS_H
+#ifndef _LINUX_BUFFER_HEAD_H
+#define _LINUX_BUFFER_HEAD_H
+
+#include <linux/types.h>
+#include <linux/fs.h>
+#include <asm/atomic.h>
+
 
 enum bh_state_bits {
 	BH_Uptodate,	/* Contains valid data */
@@ -297,4 +302,4 @@ static inline void lock_buffer(struct buffer_head * bh)
 void __buffer_error(char *file, int line);
 #define buffer_error() __buffer_error(__FILE__, __LINE__)
 
-#endif		/* BUFFER_FLAGS_H */
+#endif /* _LINUX_BUFFER_HEAD_H */