From 36211fc612d412f6cd1fb69dd094f2fa9c0b6e6c Mon Sep 17 00:00:00 2001
From: Tomohiro Kusumi <kusumi.tomohiro@gmail.com>
Date: Fri, 10 Jul 2015 23:07:28 +0900
Subject: [PATCH] sys/vfs/hammer: Add hammer_node_max_elements()

- Add inline function hammer_node_max_elements() and make
  it available to userspace.

- The relation between btree node type and # of elements is
  a part of ondisk definition, so it's better to have it in
  the same header file.
---
 sbin/hammer/cmd_show.c        |  4 ++--
 sys/vfs/hammer/hammer_btree.c | 11 ++++++-----
 sys/vfs/hammer/hammer_btree.h | 13 +++++++++++++
 3 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/sbin/hammer/cmd_show.c b/sbin/hammer/cmd_show.c
index 0c512d4e1c..2beba35dcb 100644
--- a/sbin/hammer/cmd_show.c
+++ b/sbin/hammer/cmd_show.c
@@ -170,8 +170,8 @@ print_btree_node(hammer_off_t node_offset, btree_search_t search,
 	}
 	printf(" {\n");
 
-	maxcount = (node->type == HAMMER_BTREE_TYPE_INTERNAL) ?
-		   HAMMER_BTREE_INT_ELMS : HAMMER_BTREE_LEAF_ELMS;
+	maxcount = hammer_node_max_elements(node->type);
+	assert(maxcount != -1);
 
 	for (i = 0; i < node->count && i < maxcount; ++i) {
 		elm = &node->elms[i];
diff --git a/sys/vfs/hammer/hammer_btree.c b/sys/vfs/hammer/hammer_btree.c
index 27482dc88b..d27b7538db 100644
--- a/sys/vfs/hammer/hammer_btree.c
+++ b/sys/vfs/hammer/hammer_btree.c
@@ -3048,11 +3048,12 @@ static __inline
 int
 btree_max_elements(u_int8_t type)
 {
-	if (type == HAMMER_BTREE_TYPE_LEAF)
-		return(HAMMER_BTREE_LEAF_ELMS);
-	if (type == HAMMER_BTREE_TYPE_INTERNAL)
-		return(HAMMER_BTREE_INT_ELMS);
-	panic("btree_max_elements: bad type %d", type);
+	int n;
+
+	n = hammer_node_max_elements(type);
+	if (n == -1)
+		panic("btree_max_elements: bad type %d", type);
+	return(n);
 }
 
 void
diff --git a/sys/vfs/hammer/hammer_btree.h b/sys/vfs/hammer/hammer_btree.h
index 526d59cdc1..ff664a0cab 100644
--- a/sys/vfs/hammer/hammer_btree.h
+++ b/sys/vfs/hammer/hammer_btree.h
@@ -209,6 +209,19 @@ typedef union hammer_btree_elm *hammer_btree_elm_t;
 #define HAMMER_BTREE_TYPE_RECORD	((u_int8_t)'R')
 #define HAMMER_BTREE_TYPE_DELETED	((u_int8_t)'D')
 
+static __inline
+int
+hammer_node_max_elements(u_int8_t type)
+{
+	switch (type) {
+	case HAMMER_BTREE_TYPE_LEAF:
+		return(HAMMER_BTREE_LEAF_ELMS);
+	case HAMMER_BTREE_TYPE_INTERNAL:
+		return(HAMMER_BTREE_INT_ELMS);
+	}
+	return(-1);  /* invalid type */
+}
+
 struct hammer_node_ondisk {
 	/*
 	 * B-Tree node header (64 bytes)
-- 
2.41.0