tree 3aeed58de180351e46ecb4e58f2e55c097eeed0d
parent ea64ab87cdba9e1172392d247e6526359e301f12
author Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> 1279031633 +0900
committer Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> 1279846934 +0900

nilfs2: reduce repetitive calculation of max number of child nodes

The current btree implementation repeats the same calculation on the
maximum number of child nodes.  This is because a few low level
routines use the calculation for index addressing in a btree node
block.

This reduces the calculation by explicitly passing the maximum number
of child nodes (ncmax) through their argument.

This changes parameter passing of the following functions:

 - nilfs_btree_node_dptrs
 - nilfs_btree_node_get_ptr
 - nilfs_btree_node_set_ptr
 - nilfs_btree_node_init
 - nilfs_btree_node_move_left
 - nilfs_btree_node_move_right
 - nilfs_btree_node_insert
 - nilfs_btree_node_delete, and
 - nilfs_btree_get_node

The following functions are removed:

 - nilfs_btree_node_nchildren_min
 - nilfs_btree_node_nchildren_max

Most middle level btree operations are rewritten to pass a proper
ncmax value depending on whether each occurrence of node is "root" or
not.

A constant NILFS_BTREE_ROOT_NCHILDREN_MAX is used for the root node,
whereas nilfs_btree_nchildren_per_block() function is used for
non-root nodes.  If a node could be either root or a non-root node, an
output argument of nilfs_btree_get_node() is used to set up ncmax.

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