knfsd: exportfs: add exportfs.h header

currently the export_operation structure and helpers related to it are in
fs.h.  fs.h is already far too large and there are very few places needing the
export bits, so split them off into a separate header.

[akpm@linux-foundation.org: fix cifs build]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Neil Brown <neilb@suse.de>
Cc: Steven French <sfrench@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/ocfs2/export.h

@@ -26,6 +26,8 @@
 #ifndef OCFS2_EXPORT_H
 #define OCFS2_EXPORT_H
 
+#include <linux/exportfs.h>
+
 extern struct export_operations ocfs2_export_ops;
 
 #endif /* OCFS2_EXPORT_H */