forked from Mirrors/btrfs-progs
merge on the way down during deletes
Chris Mason
David Woodhouse
parent
157a0bc7ce
commit
c6cc57e031
420
ctree.c
420
ctree.c
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@ -10,11 +10,10 @@ static int split_node(struct ctree_root *root, struct ctree_path *path,
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int level);
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static int split_leaf(struct ctree_root *root, struct ctree_path *path,
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int data_size);
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static int push_node_left(struct ctree_root *root, struct ctree_path *path,
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int level);
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static int push_node_right(struct ctree_root *root,
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struct ctree_path *path, int level);
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static int del_ptr(struct ctree_root *root, struct ctree_path *path, int level);
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static int push_node_left(struct ctree_root *root, struct tree_buffer *dst,
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struct tree_buffer *src);
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static int del_ptr(struct ctree_root *root, struct ctree_path *path, int level,
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int slot);
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inline void init_path(struct ctree_path *p)
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{
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@ -192,6 +191,138 @@ int bin_search(struct node *c, struct key *key, int *slot)
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return -1;
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}
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struct tree_buffer *read_node_slot(struct ctree_root *root,
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struct tree_buffer *parent_buf,
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int slot)
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{
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struct node *node = &parent_buf->node;
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if (slot < 0)
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return NULL;
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if (slot >= node->header.nritems)
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return NULL;
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return read_tree_block(root, node->blockptrs[slot]);
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}
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static int balance_level(struct ctree_root *root, struct ctree_path *path,
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int level)
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{
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struct tree_buffer *right_buf;
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struct tree_buffer *mid_buf;
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struct tree_buffer *left_buf;
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struct tree_buffer *parent_buf = NULL;
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struct node *right = NULL;
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struct node *mid;
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struct node *left = NULL;
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struct node *parent = NULL;
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int ret = 0;
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int wret;
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int pslot;
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int used = 0;
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int count;
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int orig_slot = path->slots[level];
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if (level == 0)
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return 0;
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mid_buf = path->nodes[level];
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mid = &mid_buf->node;
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if (level < MAX_LEVEL - 1)
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parent_buf = path->nodes[level + 1];
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pslot = path->slots[level + 1];
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if (!parent_buf) {
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struct tree_buffer *child;
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u64 blocknr = mid_buf->blocknr;
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if (mid->header.nritems != 1)
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return 0;
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/* promote the child to a root */
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child = read_node_slot(root, mid_buf, 0);
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BUG_ON(!child);
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root->node = child;
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path->nodes[level] = NULL;
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/* once for the path */
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tree_block_release(root, mid_buf);
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/* once for the root ptr */
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tree_block_release(root, mid_buf);
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return free_extent(root, blocknr, 1);
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}
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parent = &parent_buf->node;
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if (mid->header.nritems > NODEPTRS_PER_BLOCK / 4)
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return 0;
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// print_tree(root, root->node);
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left_buf = read_node_slot(root, parent_buf, pslot - 1);
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right_buf = read_node_slot(root, parent_buf, pslot + 1);
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if (right_buf) {
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right = &right_buf->node;
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used = right->header.nritems;
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count = 1;
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}
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if (left_buf) {
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left = &left_buf->node;
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used += left->header.nritems;
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orig_slot += left->header.nritems;
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count++;
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}
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if (left_buf)
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push_node_left(root, left_buf, mid_buf);
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if (right_buf) {
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push_node_left(root, mid_buf, right_buf);
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if (right->header.nritems == 0) {
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u64 blocknr = right_buf->blocknr;
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tree_block_release(root, right_buf);
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right_buf = NULL;
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right = NULL;
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wret = del_ptr(root, path, level + 1, pslot + 1);
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if (wret)
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ret = wret;
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wret = free_extent(root, blocknr, 1);
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if (wret)
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ret = wret;
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} else {
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memcpy(parent->keys + pslot + 1, right->keys,
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sizeof(struct key));
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}
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}
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if (mid->header.nritems == 0) {
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u64 blocknr = mid_buf->blocknr;
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tree_block_release(root, mid_buf);
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mid_buf = NULL;
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mid = NULL;
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wret = del_ptr(root, path, level + 1, pslot);
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if (wret)
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ret = wret;
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wret = free_extent(root, blocknr, 1);
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if (wret)
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ret = wret;
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} else
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memcpy(parent->keys + pslot, mid->keys, sizeof(struct key));
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if (left_buf) {
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if (left->header.nritems >= orig_slot) {
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left_buf->count++; // released below
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path->nodes[level] = left_buf;
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path->slots[level + 1] -= 1;
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path->slots[level] = orig_slot;
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if (mid_buf)
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tree_block_release(root, mid_buf);
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} else {
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orig_slot -= left->header.nritems;
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path->slots[level] = orig_slot;
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}
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}
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if (right_buf)
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tree_block_release(root, right_buf);
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if (left_buf)
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tree_block_release(root, left_buf);
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return ret;
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}
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/*
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* look for key in the tree. path is filled in with nodes along the way
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* if key is found, we return zero and you can find the item in the leaf
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@ -208,12 +339,14 @@ int bin_search(struct node *c, struct key *key, int *slot)
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int search_slot(struct ctree_root *root, struct key *key,
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struct ctree_path *p, int ins_len)
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{
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struct tree_buffer *b = root->node;
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struct tree_buffer *b;
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struct node *c;
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int slot;
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int ret;
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int level;
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again:
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b = root->node;
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b->count++;
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while (b) {
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c = &b->node;
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@ -236,9 +369,17 @@ int search_slot(struct ctree_root *root, struct key *key,
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b = p->nodes[level];
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c = &b->node;
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slot = p->slots[level];
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} else if (ins_len < 0) {
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int sret = balance_level(root, p, level);
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if (sret)
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return sret;
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b = p->nodes[level];
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if (!b)
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goto again;
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c = &b->node;
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slot = p->slots[level];
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}
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b = read_tree_block(root, c->blockptrs[slot]);
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continue;
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} else {
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struct leaf *l = (struct leaf *)c;
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p->slots[level] = slot;
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@ -249,9 +390,11 @@ int search_slot(struct ctree_root *root, struct key *key,
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if (sret)
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return sret;
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}
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BUG_ON(root->node->count == 1);
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return ret;
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}
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}
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BUG_ON(root->node->count == 1);
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return 1;
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}
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@ -301,161 +444,47 @@ static int fixup_low_keys(struct ctree_root *root,
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* returns 0 if some ptrs were pushed left, < 0 if there was some horrible
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* error, and > 0 if there was no room in the left hand block.
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*/
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static int push_node_left(struct ctree_root *root, struct ctree_path *path,
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int level)
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static int push_node_left(struct ctree_root *root, struct tree_buffer *dst_buf,
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struct tree_buffer *src_buf)
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{
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int slot;
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struct node *left;
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struct node *right;
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struct node *src = &src_buf->node;
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struct node *dst = &dst_buf->node;
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int push_items = 0;
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int left_nritems;
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int right_nritems;
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struct tree_buffer *t;
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struct tree_buffer *right_buf;
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int src_nritems;
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int dst_nritems;
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int ret = 0;
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int wret;
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if (level == MAX_LEVEL - 1 || path->nodes[level + 1] == 0)
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return 1;
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slot = path->slots[level + 1];
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if (slot == 0)
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return 1;
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t = read_tree_block(root,
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path->nodes[level + 1]->node.blockptrs[slot - 1]);
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left = &t->node;
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right_buf = path->nodes[level];
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right = &right_buf->node;
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left_nritems = left->header.nritems;
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right_nritems = right->header.nritems;
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push_items = NODEPTRS_PER_BLOCK - (left_nritems + 1);
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if (push_items <= 0) {
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tree_block_release(root, t);
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return 1;
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}
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if (right_nritems < push_items)
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push_items = right_nritems;
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memcpy(left->keys + left_nritems, right->keys,
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push_items * sizeof(struct key));
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memcpy(left->blockptrs + left_nritems, right->blockptrs,
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push_items * sizeof(u64));
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memmove(right->keys, right->keys + push_items,
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(right_nritems - push_items) * sizeof(struct key));
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memmove(right->blockptrs, right->blockptrs + push_items,
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(right_nritems - push_items) * sizeof(u64));
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right->header.nritems -= push_items;
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left->header.nritems += push_items;
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/* adjust the pointers going up the tree */
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wret = fixup_low_keys(root, path, right->keys, level + 1);
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if (wret < 0)
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ret = wret;
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wret = write_tree_block(root, t);
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if (wret < 0)
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ret = wret;
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wret = write_tree_block(root, right_buf);
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if (wret < 0)
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ret = wret;
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/* then fixup the leaf pointer in the path */
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if (path->slots[level] < push_items) {
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path->slots[level] += left_nritems;
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tree_block_release(root, path->nodes[level]);
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path->nodes[level] = t;
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path->slots[level + 1] -= 1;
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} else {
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path->slots[level] -= push_items;
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tree_block_release(root, t);
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}
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return ret;
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}
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/*
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* try to push data from one node into the next node right in the
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* tree. The src node is found at specified level in the path.
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* If some bytes were pushed, return 0, otherwise return 1.
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*
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* Lower nodes/leaves in the path are not touched, higher nodes may
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* be modified to reflect the push.
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*
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* The path is altered to reflect the push.
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*
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* returns 0 if some ptrs were pushed, < 0 if there was some horrible
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* error, and > 0 if there was no room in the right hand block.
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*/
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static int push_node_right(struct ctree_root *root, struct ctree_path *path,
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int level)
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{
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int slot;
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struct tree_buffer *t;
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struct tree_buffer *src_buffer;
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struct node *dst;
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struct node *src;
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int push_items = 0;
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int dst_nritems;
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int src_nritems;
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/* can't push from the root */
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if (level == MAX_LEVEL - 1 || path->nodes[level + 1] == 0)
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return 1;
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/* only try to push inside the node higher up */
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slot = path->slots[level + 1];
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if (slot == NODEPTRS_PER_BLOCK - 1)
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return 1;
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if (slot >= path->nodes[level + 1]->node.header.nritems -1)
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return 1;
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t = read_tree_block(root,
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path->nodes[level + 1]->node.blockptrs[slot + 1]);
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dst = &t->node;
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src_buffer = path->nodes[level];
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src = &src_buffer->node;
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dst_nritems = dst->header.nritems;
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src_nritems = src->header.nritems;
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push_items = NODEPTRS_PER_BLOCK - (dst_nritems + 1);
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dst_nritems = dst->header.nritems;
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push_items = NODEPTRS_PER_BLOCK - dst_nritems;
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if (push_items <= 0) {
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tree_block_release(root, t);
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return 1;
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}
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if (src_nritems < push_items)
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push_items = src_nritems;
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memmove(dst->keys + push_items, dst->keys,
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dst_nritems * sizeof(struct key));
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memcpy(dst->keys, src->keys + src_nritems - push_items,
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push_items =src_nritems;
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memcpy(dst->keys + dst_nritems, src->keys,
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push_items * sizeof(struct key));
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memmove(dst->blockptrs + push_items, dst->blockptrs,
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dst_nritems * sizeof(u64));
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memcpy(dst->blockptrs, src->blockptrs + src_nritems - push_items,
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memcpy(dst->blockptrs + dst_nritems, src->blockptrs,
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push_items * sizeof(u64));
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if (push_items < src_nritems) {
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memmove(src->keys, src->keys + push_items,
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(src_nritems - push_items) * sizeof(struct key));
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memmove(src->blockptrs, src->blockptrs + push_items,
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(src_nritems - push_items) * sizeof(u64));
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}
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src->header.nritems -= push_items;
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dst->header.nritems += push_items;
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/* adjust the pointers going up the tree */
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memcpy(path->nodes[level + 1]->node.keys + path->slots[level + 1] + 1,
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dst->keys, sizeof(struct key));
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wret = write_tree_block(root, src_buf);
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if (wret < 0)
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ret = wret;
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write_tree_block(root, path->nodes[level + 1]);
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write_tree_block(root, t);
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write_tree_block(root, src_buffer);
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/* then fixup the pointers in the path */
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if (path->slots[level] >= src->header.nritems) {
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path->slots[level] -= src->header.nritems;
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tree_block_release(root, path->nodes[level]);
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path->nodes[level] = t;
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path->slots[level + 1] += 1;
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} else {
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tree_block_release(root, t);
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}
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return 0;
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wret = write_tree_block(root, dst_buf);
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if (wret < 0)
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ret = wret;
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return ret;
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}
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/*
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@ -558,16 +587,6 @@ static int split_node(struct ctree_root *root, struct ctree_path *path,
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int ret;
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int wret;
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ret = push_node_left(root, path, level);
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if (!ret)
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return 0;
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if (ret < 0)
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return ret;
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ret = push_node_right(root, path, level);
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if (!ret)
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return 0;
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if (ret < 0)
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return ret;
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t = path->nodes[level];
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c = &t->node;
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if (t == root->node) {
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@ -1011,6 +1030,7 @@ int insert_item(struct ctree_root *root, struct key *key,
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if (leaf_free_space(leaf) < 0)
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BUG();
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check_leaf(&path, 0);
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release_path(root, &path);
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return ret;
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}
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@ -1022,77 +1042,38 @@ int insert_item(struct ctree_root *root, struct key *key,
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* continuing all the way the root if required. The root is converted into
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* a leaf if all the nodes are emptied.
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*/
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static int del_ptr(struct ctree_root *root, struct ctree_path *path, int level)
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static int del_ptr(struct ctree_root *root, struct ctree_path *path, int level,
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int slot)
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{
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int slot;
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struct tree_buffer *t;
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struct node *node;
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struct tree_buffer *parent = path->nodes[level];
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int nritems;
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u64 blocknr;
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int wret;
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int ret = 0;
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int wret;
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while(1) {
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t = path->nodes[level];
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if (!t)
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break;
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node = &t->node;
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slot = path->slots[level];
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nritems = node->header.nritems;
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node = &parent->node;
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nritems = node->header.nritems;
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if (slot != nritems -1) {
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memmove(node->keys + slot, node->keys + slot + 1,
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sizeof(struct key) * (nritems - slot - 1));
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memmove(node->blockptrs + slot,
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node->blockptrs + slot + 1,
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sizeof(u64) * (nritems - slot - 1));
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}
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node->header.nritems--;
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blocknr = t->blocknr;
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write_tree_block(root, t);
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if (node->header.nritems != 0) {
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int tslot;
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if (slot == 0) {
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wret = fixup_low_keys(root, path,
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node->keys,
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level + 1);
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if (wret)
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ret = wret;
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}
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tslot = path->slots[level + 1];
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t->count++;
|
||||
wret = push_node_left(root, path, level);
|
||||
if (wret < 0) {
|
||||
ret = wret;
|
||||
break;
|
||||
}
|
||||
if (node->header.nritems != 0) {
|
||||
wret = push_node_right(root, path, level);
|
||||
if (wret < 0) {
|
||||
ret = wret;
|
||||
break;
|
||||
}
|
||||
}
|
||||
path->slots[level + 1] = tslot;
|
||||
if (node->header.nritems != 0) {
|
||||
tree_block_release(root, t);
|
||||
break;
|
||||
}
|
||||
tree_block_release(root, t);
|
||||
}
|
||||
if (t == root->node) {
|
||||
/* just turn the root into a leaf and break */
|
||||
root->node->node.header.flags = node_level(0);
|
||||
write_tree_block(root, t);
|
||||
break;
|
||||
}
|
||||
level++;
|
||||
wret = free_extent(root, blocknr, 1);
|
||||
if (slot != nritems -1) {
|
||||
memmove(node->keys + slot, node->keys + slot + 1,
|
||||
sizeof(struct key) * (nritems - slot - 1));
|
||||
memmove(node->blockptrs + slot,
|
||||
node->blockptrs + slot + 1,
|
||||
sizeof(u64) * (nritems - slot - 1));
|
||||
}
|
||||
node->header.nritems--;
|
||||
if (node->header.nritems == 0 && parent == root->node) {
|
||||
BUG_ON(node_level(root->node->node.header.flags) != 1);
|
||||
/* just turn the root into a leaf and break */
|
||||
root->node->node.header.flags = node_level(0);
|
||||
} else if (slot == 0) {
|
||||
wret = fixup_low_keys(root, path, node->keys, level + 1);
|
||||
if (wret)
|
||||
ret = wret;
|
||||
if (!path->nodes[level])
|
||||
BUG();
|
||||
}
|
||||
wret = write_tree_block(root, parent);
|
||||
if (wret)
|
||||
ret = wret;
|
||||
return ret;
|
||||
}
|
||||
|
||||
|
|
@ -1135,7 +1116,7 @@ int del_item(struct ctree_root *root, struct ctree_path *path)
|
|||
leaf->header.flags = node_level(0);
|
||||
write_tree_block(root, leaf_buf);
|
||||
} else {
|
||||
wret = del_ptr(root, path, 1);
|
||||
wret = del_ptr(root, path, 1, path->slots[1]);
|
||||
if (wret)
|
||||
ret = wret;
|
||||
wret = free_extent(root, leaf_buf->blocknr, 1);
|
||||
|
|
@ -1172,8 +1153,7 @@ int del_item(struct ctree_root *root, struct ctree_path *path)
|
|||
}
|
||||
if (leaf->header.nritems == 0) {
|
||||
u64 blocknr = leaf_buf->blocknr;
|
||||
path->slots[1] = slot;
|
||||
wret = del_ptr(root, path, 1);
|
||||
wret = del_ptr(root, path, 1, slot);
|
||||
if (wret)
|
||||
ret = wret;
|
||||
tree_block_release(root, leaf_buf);
|
||||
|
|
|
|||
Loading…
Reference in New Issue