btrfs: move maximum limits to btrfs_tree.h

We have maximum link and name length limits, move these to btrfs_tree.h
as they're on disk limitations.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ reformat comments ]
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/ctree.h

@@ -68,19 +68,6 @@ struct reloc_control;
 
 #define BTRFS_OLDEST_GENERATION	0ULL
 
-/*
- * we can actually store much bigger names, but lets not confuse the rest
- * of linux
- */
-#define BTRFS_NAME_LEN 255
-
-/*
- * Theoretical limit is larger, but we keep this down to a sane
- * value. That should limit greatly the possibility of collisions on
- * inode ref items.
- */
-#define BTRFS_LINK_MAX 65535U
-
 #define BTRFS_EMPTY_DIR_SIZE 0
 
 #define BTRFS_DIRTY_METADATA_THRESH	SZ_32M

include/uapi/linux/btrfs_tree.h

@@ -15,6 +15,18 @@
 
 #define BTRFS_MAX_LEVEL 8
 
+/*
+ * We can actually store much bigger names, but lets not confuse the rest of
+ * linux.
+ */
+#define BTRFS_NAME_LEN 255
+
+/*
+ * Theoretical limit is larger, but we keep this down to a sane value. That
+ * should limit greatly the possibility of collisions on inode ref items.
+ */
+#define BTRFS_LINK_MAX 65535U
+
 /*
  * This header contains the structure definitions and constants used
  * by file system objects that can be retrieved using