nilfs2: move definition of struct nilfs_btree_node

This is a trivial patch to expose struct nilfs_fs_btree_node.
The struct should be exposed outside of kernel, for it is disk format.

Signed-off-by: Jiro SEKIBA <jir@unicus.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

1 files changed, 22 insertions, 0 deletions

diff --git a/include/linux/nilfs2_fs.h b/include/linux/nilfs2_fs.h
index ce520402e840..72289d2bb341 100644
--- a/include/linux/nilfs2_fs.h
+++ b/include/linux/nilfs2_fs.h
@@ -403,6 +403,28 @@ struct nilfs_segment_summary {
 #define NILFS_SS_GC     0x0010  /* segment written for cleaner operation */
 
 /**
+ * struct nilfs_btree_node - B-tree node
+ * @bn_flags: flags
+ * @bn_level: level
+ * @bn_nchildren: number of children
+ * @bn_pad: padding
+ */
+struct nilfs_btree_node {
+        __u8 bn_flags;
+        __u8 bn_level;
+        __le16 bn_nchildren;
+        __le32 bn_pad;
+};
+
+/* flags */
+#define NILFS_BTREE_NODE_ROOT   0x01
+
+/* level */
+#define NILFS_BTREE_LEVEL_DATA          0
+#define NILFS_BTREE_LEVEL_NODE_MIN      (NILFS_BTREE_LEVEL_DATA + 1)
+#define NILFS_BTREE_LEVEL_MAX           14
+
+/**
  * struct nilfs_palloc_group_desc - block group descriptor
  * @pg_nfrees: number of free entries in block group
  */