From: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Date: Tue, 13 Jul 2010 14:33:54 +0000 (+0900)
Subject: nilfs2: get maximum number of child nodes from bmap object
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=5ad2686e9266f24a0bb76b01d5c3ae29b4e149fe;p=linux-beck.git

nilfs2: get maximum number of child nodes from bmap object

The patch "reduce repetitive calculation of max number of child nodes"
gathered up the calculation of maximum number of child nodes into
nilfs_btree_nchildren_per_block() function.  This makes the function
get resultant value from a private variable in bmap object instead of
calculating it for each call.

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

diff --git a/fs/nilfs2/bmap.h b/fs/nilfs2/bmap.h
index fae83cf9c009..a20569b19929 100644
--- a/fs/nilfs2/bmap.h
+++ b/fs/nilfs2/bmap.h
@@ -105,6 +105,7 @@ static inline int nilfs_bmap_is_new_ptr(unsigned long ptr)
  * @b_last_allocated_ptr: last allocated ptr for data block
  * @b_ptr_type: pointer type
  * @b_state: state
+ * @b_nchildren_per_block: maximum number of child nodes for non-root nodes
  */
 struct nilfs_bmap {
 	union {
@@ -118,6 +119,7 @@ struct nilfs_bmap {
 	__u64 b_last_allocated_ptr;
 	int b_ptr_type;
 	int b_state;
+	__u16 b_nchildren_per_block;
 };
 
 /* pointer type */
diff --git a/fs/nilfs2/btree.c b/fs/nilfs2/btree.c
index 829e145f1353..7089d9041146 100644
--- a/fs/nilfs2/btree.c
+++ b/fs/nilfs2/btree.c
@@ -154,7 +154,7 @@ static inline int nilfs_btree_node_size(const struct nilfs_bmap *btree)
 
 static int nilfs_btree_nchildren_per_block(const struct nilfs_bmap *btree)
 {
-	return NILFS_BTREE_NODE_NCHILDREN_MAX(nilfs_btree_node_size(btree));
+	return btree->b_nchildren_per_block;
 }
 
 static inline __le64 *
@@ -2218,10 +2218,14 @@ static const struct nilfs_bmap_operations nilfs_btree_ops_gc = {
 int nilfs_btree_init(struct nilfs_bmap *bmap)
 {
 	bmap->b_ops = &nilfs_btree_ops;
+	bmap->b_nchildren_per_block =
+		NILFS_BTREE_NODE_NCHILDREN_MAX(nilfs_btree_node_size(bmap));
 	return 0;
 }
 
 void nilfs_btree_init_gc(struct nilfs_bmap *bmap)
 {
 	bmap->b_ops = &nilfs_btree_ops_gc;
+	bmap->b_nchildren_per_block =
+		NILFS_BTREE_NODE_NCHILDREN_MAX(nilfs_btree_node_size(bmap));
 }