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authorChris Mason <chris.mason@oracle.com>2007-02-24 13:39:08 -0500
committerDavid Woodhouse <dwmw2@hera.kernel.org>2007-02-24 13:39:08 -0500
commitf463391fd2bfe9041d79adaf61491c153cf41624 (patch)
tree1c40f9912e72f0a081a8fd51498e62381f36c236 /ctree.c
parent065994c9948553a4715792edb4a2c792b3ae319c (diff)
cleanup & comment
Diffstat (limited to 'ctree.c')
-rw-r--r--ctree.c28
1 files changed, 27 insertions, 1 deletions
diff --git a/ctree.c b/ctree.c
index ef8bfa83..7645ab32 100644
--- a/ctree.c
+++ b/ctree.c
@@ -110,6 +110,10 @@ int generic_bin_search(char *p, int item_size, struct key *key,
return 1;
}
+/*
+ * simple bin_search frontend that does the right thing for
+ * leaves vs nodes
+ */
int bin_search(struct node *c, struct key *key, int *slot)
{
if (is_leaf(c->header.flags)) {
@@ -130,6 +134,10 @@ int bin_search(struct node *c, struct key *key, int *slot)
*
* If the key isn't found, the path points to the slot where it should
* be inserted.
+ *
+ * if ins_len > 0, nodes and leaves will be split as we walk down the
+ * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
+ * possible)
*/
int search_slot(struct ctree_root *root, struct key *key,
struct ctree_path *p, int ins_len)
@@ -379,6 +387,11 @@ int push_node_right(struct ctree_root *root, struct ctree_path *path, int level)
return 0;
}
+/*
+ * helper function to insert a new root level in the tree.
+ * A new node is allocated, and a single item is inserted to
+ * point to the existing root
+ */
static int insert_new_root(struct ctree_root *root,
struct ctree_path *path, int level)
{
@@ -417,6 +430,7 @@ static int insert_new_root(struct ctree_root *root,
/*
* worker function to insert a single pointer in a node.
* the node should have enough room for the pointer already
+ *
* slot and level indicate where you want the key to go, and
* blocknr is the block the key points to.
*/
@@ -449,6 +463,13 @@ int insert_ptr(struct ctree_root *root,
return 0;
}
+/*
+ * split the node at the specified level in path in two.
+ * The path is corrected to point to the appropriate node after the split
+ *
+ * Before splitting this tries to make some room in the node by pushing
+ * left and right, if either one works, it returns right away.
+ */
int split_node(struct ctree_root *root, struct ctree_path *path, int level)
{
struct tree_buffer *t;
@@ -744,10 +765,12 @@ int split_leaf(struct ctree_root *root, struct ctree_path *path, int data_size)
right = &right_buffer->leaf;
memset(right, 0, sizeof(*right));
if (mid <= slot) {
+ /* FIXME, just alloc a new leaf here */
if (leaf_space_used(l, mid, nritems - mid) + space_needed >
LEAF_DATA_SIZE)
BUG();
} else {
+ /* FIXME, just alloc a new leaf here */
if (leaf_space_used(l, 0, mid + 1) + space_needed >
LEAF_DATA_SIZE)
BUG();
@@ -983,6 +1006,10 @@ int del_item(struct ctree_root *root, struct ctree_path *path)
return 0;
}
+/*
+ * walk up the tree as far as required to find the next leaf.
+ * returns 0 if it found something or -1 if there are no greater leaves.
+ */
int next_leaf(struct ctree_root *root, struct ctree_path *path)
{
int slot;
@@ -1044,7 +1071,6 @@ int main() {
root = open_ctree("dbfile", &super);
-
srand(55);
for (i = 0; i < run_size; i++) {
buf = malloc(64);