}
}
+/*
+ * The leaf data grows from end-to-front in the node.
+ * this returns the address of the start of the last item,
+ * which is the stop of the leaf data stack
+ */
static inline unsigned int leaf_data_end(struct leaf *leaf)
{
unsigned int nr = leaf->header.nritems;
return leaf->items[nr-1].offset;
}
+/*
+ * The space between the end of the leaf items and
+ * the start of the leaf data. IOW, how much room
+ * the leaf has left for both items and data
+ */
static inline int leaf_free_space(struct leaf *leaf)
{
int data_end = leaf_data_end(leaf);
return (char *)(leaf->data + data_end) - (char *)items_end;
}
+/*
+ * compare two keys in a memcmp fashion
+ */
int comp_keys(struct key *k1, struct key *k2)
{
if (k1->objectid > k2->objectid)
return -1;
return 0;
}
+
+/*
+ * search for key in the array p. items p are item_size apart
+ * and there are 'max' items in p
+ * the slot in the array is returned via slot, and it points to
+ * the place where you would insert key if it is not found in
+ * the array.
+ *
+ * slot may point to max if the key is bigger than all of the keys
+ */
int generic_bin_search(char *p, int item_size, struct key *key,
int max, int *slot)
{
return -1;
}
+/*
+ * look for key in the tree. path is filled in with nodes along the way
+ * if key is found, we return zero and you can find the item in the leaf
+ * level of the path (level 0)
+ *
+ * If the key isn't found, the path points to the slot where it should
+ * be inserted.
+ */
int search_slot(struct ctree_root *root, struct key *key, struct ctree_path *p)
{
struct tree_buffer *b = root->node;
return -1;
}
+/*
+ * adjust the pointers going up the tree, starting at level
+ * making sure the right key of each node is points to 'key'.
+ * This is used after shifting pointers to the left, so it stops
+ * fixing up pointers when a given leaf/node is not in slot 0 of the
+ * higher levels
+ */
static void fixup_low_keys(struct ctree_root *root,
struct ctree_path *path, struct key *key,
int level)
{
int i;
- /* adjust the pointers going up the tree */
for (i = level; i < MAX_LEVEL; i++) {
struct node *t;
int tslot = path->slots[i];
}
}
-int __insert_ptr(struct ctree_root *root,
- struct ctree_path *path, struct key *key,
- u64 blocknr, int slot, int level)
-{
- struct node *c;
- struct node *lower;
- struct key *lower_key;
- int nritems;
- /* need a new root */
- if (!path->nodes[level]) {
- struct tree_buffer *t;
- t = alloc_free_block(root);
- c = &t->node;
- memset(c, 0, sizeof(c));
- c->header.nritems = 2;
- c->header.flags = node_level(level);
- c->header.blocknr = t->blocknr;
- lower = &path->nodes[level-1]->node;
- if (is_leaf(lower->header.flags))
- lower_key = &((struct leaf *)lower)->items[0].key;
- else
- lower_key = lower->keys;
- memcpy(c->keys, lower_key, sizeof(struct key));
- memcpy(c->keys + 1, key, sizeof(struct key));
- c->blockptrs[0] = path->nodes[level-1]->blocknr;
- c->blockptrs[1] = blocknr;
- /* the path has an extra ref to root->node */
- tree_block_release(root, root->node);
- root->node = t;
- t->count++;
- write_tree_block(root, t);
- path->nodes[level] = t;
- path->slots[level] = 0;
- if (c->keys[1].objectid == 0)
- BUG();
- return 0;
- }
- lower = &path->nodes[level]->node;
- nritems = lower->header.nritems;
- if (slot > nritems)
- BUG();
- if (nritems == NODEPTRS_PER_BLOCK)
- BUG();
- if (slot != nritems) {
- memmove(lower->keys + slot + 1, lower->keys + slot,
- (nritems - slot) * sizeof(struct key));
- memmove(lower->blockptrs + slot + 1, lower->blockptrs + slot,
- (nritems - slot) * sizeof(u64));
- }
- memcpy(lower->keys + slot, key, sizeof(struct key));
- lower->blockptrs[slot] = blocknr;
- lower->header.nritems++;
- if (lower->keys[1].objectid == 0)
- BUG();
- write_tree_block(root, path->nodes[level]);
- return 0;
-}
-
+/*
+ * try to push data from one node into the next node left in the
+ * tree. The src node is found at specified level in the path.
+ * If some bytes were pushed, return 0, otherwise return 1.
+ *
+ * Lower nodes/leaves in the path are not touched, higher nodes may
+ * be modified to reflect the push.
+ *
+ * The path is altered to reflect the push.
+ */
int push_node_left(struct ctree_root *root, struct ctree_path *path, int level)
{
int slot;
return 0;
}
+/*
+ * try to push data from one node into the next node right in the
+ * tree. The src node is found at specified level in the path.
+ * If some bytes were pushed, return 0, otherwise return 1.
+ *
+ * Lower nodes/leaves in the path are not touched, higher nodes may
+ * be modified to reflect the push.
+ *
+ * The path is altered to reflect the push.
+ */
int push_node_right(struct ctree_root *root, struct ctree_path *path, int level)
{
int slot;
int dst_nritems;
int src_nritems;
+ /* can't push from the root */
if (level == MAX_LEVEL - 1 || path->nodes[level + 1] == 0)
return 1;
+
+ /* only try to push inside the node higher up */
slot = path->slots[level + 1];
if (slot == NODEPTRS_PER_BLOCK - 1)
return 1;
write_tree_block(root, t);
write_tree_block(root, src_buffer);
- /* then fixup the leaf pointer in the path */
+ /* then fixup the pointers in the path */
if (path->slots[level] >= src->header.nritems) {
path->slots[level] -= src->header.nritems;
tree_block_release(root, path->nodes[level]);
return 0;
}
+/*
+ * 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.
+ */
+int __insert_ptr(struct ctree_root *root,
+ struct ctree_path *path, struct key *key,
+ u64 blocknr, int slot, int level)
+{
+ struct node *c;
+ struct node *lower;
+ struct key *lower_key;
+ int nritems;
+ /* need a new root */
+ if (!path->nodes[level]) {
+ struct tree_buffer *t;
+ t = alloc_free_block(root);
+ c = &t->node;
+ memset(c, 0, sizeof(c));
+ c->header.nritems = 2;
+ c->header.flags = node_level(level);
+ c->header.blocknr = t->blocknr;
+ lower = &path->nodes[level-1]->node;
+ if (is_leaf(lower->header.flags))
+ lower_key = &((struct leaf *)lower)->items[0].key;
+ else
+ lower_key = lower->keys;
+ memcpy(c->keys, lower_key, sizeof(struct key));
+ memcpy(c->keys + 1, key, sizeof(struct key));
+ c->blockptrs[0] = path->nodes[level-1]->blocknr;
+ c->blockptrs[1] = blocknr;
+ /* the path has an extra ref to root->node */
+ tree_block_release(root, root->node);
+ root->node = t;
+ t->count++;
+ write_tree_block(root, t);
+ path->nodes[level] = t;
+ path->slots[level] = 0;
+ if (c->keys[1].objectid == 0)
+ BUG();
+ return 0;
+ }
+ lower = &path->nodes[level]->node;
+ nritems = lower->header.nritems;
+ if (slot > nritems)
+ BUG();
+ if (nritems == NODEPTRS_PER_BLOCK)
+ BUG();
+ if (slot != nritems) {
+ memmove(lower->keys + slot + 1, lower->keys + slot,
+ (nritems - slot) * sizeof(struct key));
+ memmove(lower->blockptrs + slot + 1, lower->blockptrs + slot,
+ (nritems - slot) * sizeof(u64));
+ }
+ memcpy(lower->keys + slot, key, sizeof(struct key));
+ lower->blockptrs[slot] = blocknr;
+ lower->header.nritems++;
+ if (lower->keys[1].objectid == 0)
+ BUG();
+ write_tree_block(root, path->nodes[level]);
+ return 0;
+}
+
+
+/*
+ * insert a key,blocknr pair into the tree at a given level
+ * If the node at that level in the path doesn't have room,
+ * it is split or shifted as appropriate.
+ */
int insert_ptr(struct ctree_root *root,
struct ctree_path *path, struct key *key,
u64 blocknr, int level)
int mid;
int bal_start = -1;
+ /*
+ * check to see if we need to make room in the node for this
+ * pointer. If we do, keep walking the tree, making sure there
+ * is enough room in each level for the required insertions.
+ *
+ * The bal array is filled in with any nodes to be inserted
+ * due to splitting. Once we've done all the splitting required
+ * do the inserts based on the data in the bal array.
+ */
memset(bal, 0, ARRAY_SIZE(bal));
while(t && t->node.header.nritems == NODEPTRS_PER_BLOCK) {
c = &t->node;
bal_level += 1;
t = path->nodes[bal_level];
}
+ /*
+ * bal_start tells us the first level in the tree that needed to
+ * be split. Go through the bal array inserting the new nodes
+ * as needed. The path is fixed as we go.
+ */
while(bal_start > 0) {
b_buffer = bal[bal_start];
c = &path->nodes[bal_start]->node;
if (!bal[bal_start])
break;
}
+ /* Now that the tree has room, insert the requested pointer */
return __insert_ptr(root, path, key, blocknr, path->slots[level] + 1,
level);
}
+/*
+ * how many bytes are required to store the items in a leaf. start
+ * and nr indicate which items in the leaf to check. This totals up the
+ * space used both by the item structs and the item data
+ */
int leaf_space_used(struct leaf *l, int start, int nr)
{
int data_len;
return data_len;
}
+/*
+ * push some data in the path leaf to the left, trying to free up at
+ * least data_size bytes. returns zero if the push worked, nonzero otherwise
+ */
int push_leaf_left(struct ctree_root *root, struct ctree_path *path,
int data_size)
{
return 0;
}
+/*
+ * split the path's leaf in two, making sure there is at least data_size
+ * available for the resulting leaf level of the path.
+ */
int split_leaf(struct ctree_root *root, struct ctree_path *path, int data_size)
{
struct tree_buffer *l_buf = path->nodes[0];
l->data + leaf_data_end(l), data_copy_size);
rt_data_off = LEAF_DATA_SIZE -
(l->items[mid].offset + l->items[mid].size);
- for (i = 0; i < right->header.nritems; i++) {
+
+ for (i = 0; i < right->header.nritems; i++)
right->items[i].offset += rt_data_off;
- }
+
l->header.nritems = mid;
ret = insert_ptr(root, path, &right->items[0].key,
right_buffer->blocknr, 1);
return ret;
}
+/*
+ * Given a key and some data, insert an item into the tree.
+ * This does all the path init required, making room in the tree if needed.
+ */
int insert_item(struct ctree_root *root, struct key *key,
void *data, int data_size)
{
unsigned int data_end;
struct ctree_path path;
+ /* create a root if there isn't one */
if (!root->node) {
struct tree_buffer *t;
t = alloc_free_block(root);
slot_orig = path.slots[0];
leaf_buf = path.nodes[0];
leaf = &leaf_buf->leaf;
+
+ /* make room if needed */
if (leaf_free_space(leaf) < sizeof(struct item) + data_size) {
split_leaf(root, &path, data_size);
leaf_buf = path.nodes[0];
data_end, old_data - data_end);
data_end = old_data;
}
+ /* copy the new data in */
memcpy(&leaf->items[slot].key, key, sizeof(struct key));
leaf->items[slot].offset = data_end - data_size;
leaf->items[slot].size = data_size;
return 0;
}
+/*
+ * delete the pointer from a given level in the path. The path is not
+ * fixed up, so after calling this it is not valid at that level.
+ *
+ * If the delete empties a node, the node is removed from the tree,
+ * continuing all the way the root if required. The root is converted into
+ * a leaf if all the nodes are emptied.
+ */
int del_ptr(struct ctree_root *root, struct ctree_path *path, int level)
{
int slot;
return 0;
}
+/*
+ * delete the item at the leaf level in path. If that empties
+ * the leaf, remove it from the tree
+ */
int del_item(struct ctree_root *root, struct ctree_path *path)
{
int slot;
(leaf->header.nritems - slot - 1));
}
leaf->header.nritems -= 1;
+ /* delete the leaf if we've emptied it */
if (leaf->header.nritems == 0) {
if (leaf_buf == root->node) {
leaf->header.flags = node_level(0);
if (slot == 0)
fixup_low_keys(root, path, &leaf->items[0].key, 1);
write_tree_block(root, leaf_buf);
+ /* delete the leaf if it is mostly empty */
if (leaf_space_used(leaf, 0, leaf->header.nritems) <
LEAF_DATA_SIZE / 4) {
/* push_leaf_left fixes the path.
int i;
int num;
int ret;
- int run_size = 1000000;
+ int run_size = 25000;
int max_key = 100000000;
int tree_size = 0;
struct ctree_path path;
projects / linux-2.6-block.git / commitdiff