btrfs: add forward declarations and headers, part 1

Do a cleanup in the short headers:

- add forward declarations for types referenced by pointers
- add includes when types need them

This fixes potential compilation problems if the headers are reordered
or the missing includes are not provided indirectly.

Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/fs/btrfs/export.h b/fs/btrfs/export.h
index eba6bc4f5a61..464582273af9 100644
--- a/fs/btrfs/export.h
+++ b/fs/btrfs/export.h
@@ -4,6 +4,10 @@
 #define BTRFS_EXPORT_H
 
 #include <linux/exportfs.h>
+#include <linux/types.h>
+
+struct dentry;
+struct super_block;
 
 extern const struct export_operations btrfs_export_ops;