Btrfs: Initial checkin, basic working tree code
authorChris Mason <chris.mason@oracle.com>
Fri, 26 Jan 2007 20:51:26 +0000 (15:51 -0500)
committerDavid Woodhouse <dwmw2@hera.kernel.org>
Fri, 26 Jan 2007 20:51:26 +0000 (15:51 -0500)
Signed-off-by: Chris Mason <chris.mason@oracle.com>
fs/btrfs/ctree.c [new file with mode: 0644]

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
new file mode 100644 (file)
index 0000000..893fd56
--- /dev/null
@@ -0,0 +1,810 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include "kerncompat.h"
+
+#define BLOCKSIZE 4096
+
+struct key {
+       u64 objectid;
+       u32 flags;
+       u64 offset;
+} __attribute__ ((__packed__));
+
+struct header {
+       u64 fsid[2]; /* FS specific uuid */
+       u64 blocknum;
+       u64 parentid;
+       u32 csum;
+       u32 ham;
+       u16 nritems;
+       u16 flags;
+} __attribute__ ((__packed__));
+
+#define NODEPTRS_PER_BLOCK ((BLOCKSIZE - sizeof(struct header)) / \
+                           (sizeof(struct key) + sizeof(u64)))
+
+#define LEVEL_BITS 3
+#define MAX_LEVEL (1 << LEVEL_BITS)
+#define node_level(f) ((f) & (MAX_LEVEL-1))
+#define is_leaf(f) (node_level(f) == 0)
+
+struct ctree_root {
+       struct node *node;
+};
+
+struct item {
+       struct key key;
+       u16 offset;
+       u16 size;
+} __attribute__ ((__packed__));
+
+#define LEAF_DATA_SIZE (BLOCKSIZE - sizeof(struct header))
+struct leaf {
+       struct header header;
+       union {
+               struct item items[LEAF_DATA_SIZE/sizeof(struct item)];
+               u8 data[BLOCKSIZE-sizeof(struct header)];
+       };
+} __attribute__ ((__packed__));
+
+struct node {
+       struct header header;
+       struct key keys[NODEPTRS_PER_BLOCK];
+       u64 blockptrs[NODEPTRS_PER_BLOCK];
+} __attribute__ ((__packed__));
+
+struct ctree_path {
+       struct node *nodes[MAX_LEVEL];
+       int slots[MAX_LEVEL];
+};
+
+static inline void init_path(struct ctree_path *p)
+{
+       memset(p, 0, sizeof(*p));
+}
+
+static inline unsigned int leaf_data_end(struct leaf *leaf)
+{
+       unsigned int nr = leaf->header.nritems;
+       if (nr == 0)
+               return ARRAY_SIZE(leaf->data);
+       return leaf->items[nr-1].offset;
+}
+
+static inline int leaf_free_space(struct leaf *leaf)
+{
+       int data_end = leaf_data_end(leaf);
+       int nritems = leaf->header.nritems;
+       char *items_end = (char *)(leaf->items + nritems + 1);
+       return (char *)(leaf->data + data_end) - (char *)items_end;
+}
+
+int comp_keys(struct key *k1, struct key *k2)
+{
+       if (k1->objectid > k2->objectid)
+               return 1;
+       if (k1->objectid < k2->objectid)
+               return -1;
+       if (k1->flags > k2->flags)
+               return 1;
+       if (k1->flags < k2->flags)
+               return -1;
+       if (k1->offset > k2->offset)
+               return 1;
+       if (k1->offset < k2->offset)
+               return -1;
+       return 0;
+}
+int generic_bin_search(char *p, int item_size, struct key *key,
+                      int max, int *slot)
+{
+       int low = 0;
+       int high = max;
+       int mid;
+       int ret;
+       struct key *tmp;
+
+       while(low < high) {
+               mid = (low + high) / 2;
+               tmp = (struct key *)(p + mid * item_size);
+               ret = comp_keys(tmp, key);
+
+               if (ret < 0)
+                       low = mid + 1;
+               else if (ret > 0)
+                       high = mid;
+               else {
+                       *slot = mid;
+                       return 0;
+               }
+       }
+       *slot = low;
+       return 1;
+}
+
+int bin_search(struct node *c, struct key *key, int *slot)
+{
+       if (is_leaf(c->header.flags)) {
+               struct leaf *l = (struct leaf *)c;
+               return generic_bin_search((void *)l->items, sizeof(struct item),
+                                         key, c->header.nritems, slot);
+       } else {
+               return generic_bin_search((void *)c->keys, sizeof(struct key),
+                                         key, c->header.nritems, slot);
+       }
+       return -1;
+}
+
+void *read_block(u64 blocknum)
+{
+       return (void *)blocknum;
+}
+
+int search_slot(struct ctree_root *root, struct key *key, struct ctree_path *p)
+{
+       struct node *c = root->node;
+       int slot;
+       int ret;
+       int level;
+       while (c) {
+               level = node_level(c->header.flags);
+               p->nodes[level] = c;
+               ret = bin_search(c, key, &slot);
+               if (!is_leaf(c->header.flags)) {
+                       if (ret && slot > 0)
+                               slot -= 1;
+                       p->slots[level] = slot;
+                       c = read_block(c->blockptrs[slot]);
+                       continue;
+               } else {
+                       p->slots[level] = slot;
+                       return ret;
+               }
+       }
+       return -1;
+}
+
+static void fixup_low_keys(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 = path->nodes[i];
+               int tslot = path->slots[i];
+               if (!t)
+                       break;
+               memcpy(t->keys + tslot, key, sizeof(*key));
+               if (tslot != 0)
+                       break;
+       }
+}
+
+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]) {
+               c = malloc(sizeof(struct node));
+               memset(c, 0, sizeof(c));
+               c->header.nritems = 2;
+               c->header.flags = node_level(level);
+               lower = path->nodes[level-1];
+               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] = (u64)lower;
+               c->blockptrs[1] = blocknr;
+               root->node = c;
+               path->nodes[level] = c;
+               path->slots[level] = 0;
+               if (c->keys[1].objectid == 0)
+                       BUG();
+               return 0;
+       }
+       lower = path->nodes[level];
+       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();
+       return 0;
+}
+
+int push_node_left(struct ctree_root *root, struct ctree_path *path, int level)
+{
+       int slot;
+       struct node *left;
+       struct node *right;
+       int push_items = 0;
+       int left_nritems;
+       int right_nritems;
+
+       if (level == MAX_LEVEL - 1 || path->nodes[level + 1] == 0)
+               return 1;
+       slot = path->slots[level + 1];
+       if (slot == 0)
+               return 1;
+
+       left = read_block(path->nodes[level + 1]->blockptrs[slot - 1]);
+       right = path->nodes[level];
+       left_nritems = left->header.nritems;
+       right_nritems = right->header.nritems;
+       push_items = NODEPTRS_PER_BLOCK - (left_nritems + 1);
+       if (push_items <= 0)
+               return 1;
+
+       if (right_nritems < push_items)
+               push_items = right_nritems;
+       memcpy(left->keys + left_nritems, right->keys,
+               push_items * sizeof(struct key));
+       memcpy(left->blockptrs + left_nritems, right->blockptrs,
+               push_items * sizeof(u64));
+       memmove(right->keys, right->keys + push_items,
+               (right_nritems - push_items) * sizeof(struct key));
+       memmove(right->blockptrs, right->blockptrs + push_items,
+               (right_nritems - push_items) * sizeof(u64));
+       right->header.nritems -= push_items;
+       left->header.nritems += push_items;
+
+       /* adjust the pointers going up the tree */
+       fixup_low_keys(path, right->keys, level + 1);
+
+       /* then fixup the leaf pointer in the path */
+       if (path->slots[level] < push_items) {
+               path->slots[level] += left_nritems;
+               path->nodes[level] = (struct node*)left;
+               path->slots[level + 1] -= 1;
+       } else {
+               path->slots[level] -= push_items;
+       }
+       return 0;
+}
+
+int push_node_right(struct ctree_root *root, struct ctree_path *path, int level)
+{
+       int slot;
+       struct node *dst;
+       struct node *src;
+       int push_items = 0;
+       int dst_nritems;
+       int src_nritems;
+
+       if (level == MAX_LEVEL - 1 || path->nodes[level + 1] == 0)
+               return 1;
+       slot = path->slots[level + 1];
+       if (slot == NODEPTRS_PER_BLOCK - 1)
+               return 1;
+
+       if (slot >= path->nodes[level + 1]->header.nritems -1)
+               return 1;
+
+       dst = read_block(path->nodes[level + 1]->blockptrs[slot + 1]);
+       src = path->nodes[level];
+       dst_nritems = dst->header.nritems;
+       src_nritems = src->header.nritems;
+       push_items = NODEPTRS_PER_BLOCK - (dst_nritems + 1);
+       if (push_items <= 0)
+               return 1;
+
+       if (src_nritems < push_items)
+               push_items = src_nritems;
+       memmove(dst->keys + push_items, dst->keys,
+               dst_nritems * sizeof(struct key));
+       memcpy(dst->keys, src->keys + src_nritems - push_items,
+               push_items * sizeof(struct key));
+
+       memmove(dst->blockptrs + push_items, dst->blockptrs,
+               dst_nritems * sizeof(u64));
+       memcpy(dst->blockptrs, src->blockptrs + src_nritems - push_items,
+               push_items * sizeof(u64));
+
+       src->header.nritems -= push_items;
+       dst->header.nritems += push_items;
+
+       /* adjust the pointers going up the tree */
+       memcpy(path->nodes[level + 1]->keys + path->slots[level + 1] + 1,
+               dst->keys, sizeof(struct key));
+       /* then fixup the leaf pointer in the path */
+       if (path->slots[level] >= src->header.nritems) {
+               path->slots[level] -= src->header.nritems;
+               path->nodes[level] = (struct node*)dst;
+               path->slots[level + 1] += 1;
+       }
+       return 0;
+}
+
+int insert_ptr(struct ctree_root *root,
+               struct ctree_path *path, struct key *key,
+               u64 blocknr, int level)
+{
+       struct node *c = path->nodes[level];
+       struct node *b;
+       struct node *bal[MAX_LEVEL];
+       int bal_level = level;
+       int mid;
+       int bal_start = -1;
+
+       memset(bal, 0, ARRAY_SIZE(bal));
+       while(c && c->header.nritems == NODEPTRS_PER_BLOCK) {
+               if (push_node_left(root, path,
+                  node_level(c->header.flags)) == 0)
+                       break;
+               if (push_node_right(root, path,
+                  node_level(c->header.flags)) == 0)
+                       break;
+               bal_start = bal_level;
+               if (bal_level == MAX_LEVEL - 1)
+                       BUG();
+               b = malloc(sizeof(struct node));
+               b->header.flags = c->header.flags;
+               mid = (c->header.nritems + 1) / 2;
+               memcpy(b->keys, c->keys + mid,
+                       (c->header.nritems - mid) * sizeof(struct key));
+               memcpy(b->blockptrs, c->blockptrs + mid,
+                       (c->header.nritems - mid) * sizeof(u64));
+               b->header.nritems = c->header.nritems - mid;
+               c->header.nritems = mid;
+               bal[bal_level] = b;
+               if (bal_level == MAX_LEVEL - 1)
+                       break;
+               bal_level += 1;
+               c = path->nodes[bal_level];
+       }
+       while(bal_start > 0) {
+               b = bal[bal_start];
+               c = path->nodes[bal_start];
+               __insert_ptr(root, path, b->keys, (u64)b,
+                               path->slots[bal_start + 1] + 1, bal_start + 1);
+               if (path->slots[bal_start] >= c->header.nritems) {
+                       path->slots[bal_start] -= c->header.nritems;
+                       path->nodes[bal_start] = b;
+                       path->slots[bal_start + 1] += 1;
+               }
+               bal_start--;
+               if (!bal[bal_start])
+                       break;
+       }
+       return __insert_ptr(root, path, key, blocknr, path->slots[level] + 1,
+                           level);
+}
+
+int leaf_space_used(struct leaf *l, int start, int nr)
+{
+       int data_len;
+       int end = start + nr - 1;
+
+       if (!nr)
+               return 0;
+       data_len = l->items[start].offset + l->items[start].size;
+       data_len = data_len - l->items[end].offset;
+       data_len += sizeof(struct item) * nr;
+       return data_len;
+}
+
+int push_leaf_left(struct ctree_root *root, struct ctree_path *path,
+                  int data_size)
+{
+       struct leaf *right = (struct leaf *)path->nodes[0];
+       struct leaf *left;
+       int slot;
+       int i;
+       int free_space;
+       int push_space = 0;
+       int push_items = 0;
+       struct item *item;
+       int old_left_nritems;
+
+       slot = path->slots[1];
+       if (slot == 0) {
+               return 1;
+       }
+       if (!path->nodes[1]) {
+               return 1;
+       }
+       left = read_block(path->nodes[1]->blockptrs[slot - 1]);
+       free_space = leaf_free_space(left);
+       if (free_space < data_size + sizeof(struct item)) {
+               return 1;
+       }
+       for (i = 0; i < right->header.nritems; i++) {
+               item = right->items + i;
+               if (path->slots[0] == i)
+                       push_space += data_size + sizeof(*item);
+               if (item->size + sizeof(*item) + push_space > free_space)
+                       break;
+               push_items++;
+               push_space += item->size + sizeof(*item);
+       }
+       if (push_items == 0) {
+               return 1;
+       }
+       /* push data from right to left */
+       memcpy(left->items + left->header.nritems,
+               right->items, push_items * sizeof(struct item));
+       push_space = LEAF_DATA_SIZE - right->items[push_items -1].offset;
+       memcpy(left->data + leaf_data_end(left) - push_space,
+               right->data + right->items[push_items - 1].offset,
+               push_space);
+       old_left_nritems = left->header.nritems;
+       for(i = old_left_nritems; i < old_left_nritems + push_items; i++) {
+               left->items[i].offset -= LEAF_DATA_SIZE -
+                       left->items[old_left_nritems -1].offset;
+       }
+       left->header.nritems += push_items;
+
+       /* fixup right node */
+       push_space = right->items[push_items-1].offset - leaf_data_end(right);
+       memmove(right->data + LEAF_DATA_SIZE - push_space, right->data +
+               leaf_data_end(right), push_space);
+       memmove(right->items, right->items + push_items,
+               (right->header.nritems - push_items) * sizeof(struct item));
+       right->header.nritems -= push_items;
+       push_space = LEAF_DATA_SIZE;
+       for (i = 0; i < right->header.nritems; i++) {
+               right->items[i].offset = push_space - right->items[i].size;
+               push_space = right->items[i].offset;
+       }
+       fixup_low_keys(path, &right->items[0].key, 1);
+
+       /* then fixup the leaf pointer in the path */
+       if (path->slots[0] < push_items) {
+               path->slots[0] += old_left_nritems;
+               path->nodes[0] = (struct node*)left;
+               path->slots[1] -= 1;
+       } else {
+               path->slots[0] -= push_items;
+       }
+       return 0;
+}
+
+int split_leaf(struct ctree_root *root, struct ctree_path *path, int data_size)
+{
+       struct leaf *l = (struct leaf *)path->nodes[0];
+       int nritems = l->header.nritems;
+       int mid = (nritems + 1)/ 2;
+       int slot = path->slots[0];
+       struct leaf *right;
+       int space_needed = data_size + sizeof(struct item);
+       int data_copy_size;
+       int rt_data_off;
+       int i;
+       int ret;
+
+       if (push_leaf_left(root, path, data_size) == 0) {
+               return 0;
+       }
+       right = malloc(sizeof(struct leaf));
+       memset(right, 0, sizeof(*right));
+       if (mid <= slot) {
+               if (leaf_space_used(l, mid, nritems - mid) + space_needed >
+                       LEAF_DATA_SIZE)
+                       BUG();
+       } else {
+               if (leaf_space_used(l, 0, mid + 1) + space_needed >
+                       LEAF_DATA_SIZE)
+                       BUG();
+       }
+       right->header.nritems = nritems - mid;
+       data_copy_size = l->items[mid].offset + l->items[mid].size -
+                        leaf_data_end(l);
+       memcpy(right->items, l->items + mid,
+              (nritems - mid) * sizeof(struct item));
+       memcpy(right->data + LEAF_DATA_SIZE - data_copy_size,
+              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++) {
+               right->items[i].offset += rt_data_off;
+       }
+       l->header.nritems = mid;
+       ret = insert_ptr(root, path, &right->items[0].key,
+                         (u64)right, 1);
+       if (mid <= slot) {
+               path->nodes[0] = (struct node *)right;
+               path->slots[0] -= mid;
+               path->slots[1] += 1;
+       }
+       return ret;
+}
+
+int insert_item(struct ctree_root *root, struct key *key,
+                         void *data, int data_size)
+{
+       int ret;
+       int slot;
+       struct leaf *leaf;
+       unsigned int nritems;
+       unsigned int data_end;
+       struct ctree_path path;
+
+       init_path(&path);
+       ret = search_slot(root, key, &path);
+       if (ret == 0)
+               return -EEXIST;
+
+       leaf = (struct leaf *)path.nodes[0];
+       if (leaf_free_space(leaf) <  sizeof(struct item) + data_size)
+               split_leaf(root, &path, data_size);
+       leaf = (struct leaf *)path.nodes[0];
+       nritems = leaf->header.nritems;
+       data_end = leaf_data_end(leaf);
+       if (leaf_free_space(leaf) <  sizeof(struct item) + data_size)
+               BUG();
+
+       slot = path.slots[0];
+       if (slot == 0)
+               fixup_low_keys(&path, key, 1);
+       if (slot != nritems) {
+               int i;
+               unsigned int old_data = leaf->items[slot].offset +
+                                       leaf->items[slot].size;
+
+               /*
+                * item0..itemN ... dataN.offset..dataN.size .. data0.size
+                */
+               /* first correct the data pointers */
+               for (i = slot; i < nritems; i++)
+                       leaf->items[i].offset -= data_size;
+
+               /* shift the items */
+               memmove(leaf->items + slot + 1, leaf->items + slot,
+                       (nritems - slot) * sizeof(struct item));
+
+               /* shift the data */
+               memmove(leaf->data + data_end - data_size, leaf->data +
+                       data_end, old_data - data_end);
+               data_end = old_data;
+       }
+       memcpy(&leaf->items[slot].key, key, sizeof(struct key));
+       leaf->items[slot].offset = data_end - data_size;
+       leaf->items[slot].size = data_size;
+       memcpy(leaf->data + data_end - data_size, data, data_size);
+       leaf->header.nritems += 1;
+       if (leaf_free_space(leaf) < 0)
+               BUG();
+       return 0;
+}
+
+int del_ptr(struct ctree_root *root, struct ctree_path *path, int level)
+{
+       int slot;
+       struct node *node;
+       int nritems;
+
+       while(1) {
+               node = path->nodes[level];
+               if (!node)
+                       break;
+               slot = path->slots[level];
+               nritems = node->header.nritems;
+
+               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) {
+                       int tslot;
+                       if (slot == 0)
+                               fixup_low_keys(path, node->keys, level + 1);
+                       tslot = path->slots[level+1];
+                       push_node_left(root, path, level);
+                       if (node->header.nritems) {
+                               push_node_right(root, path, level);
+                       }
+                       path->slots[level+1] = tslot;
+                       if (node->header.nritems)
+                               break;
+               }
+               if (node == root->node) {
+                       printf("root is now null!\n");
+                       root->node = NULL;
+                       break;
+               }
+               level++;
+               if (!path->nodes[level])
+                       BUG();
+               free(node);
+       }
+       return 0;
+}
+
+int del_item(struct ctree_root *root, struct key *key)
+{
+       int ret;
+       int slot;
+       struct leaf *leaf;
+       struct ctree_path path;
+       int doff;
+       int dsize;
+
+       init_path(&path);
+       ret = search_slot(root, key, &path);
+       if (ret != 0)
+               return -1;
+
+       leaf = (struct leaf *)path.nodes[0];
+       slot = path.slots[0];
+       doff = leaf->items[slot].offset;
+       dsize = leaf->items[slot].size;
+
+       if (slot != leaf->header.nritems - 1) {
+               int i;
+               int data_end = leaf_data_end(leaf);
+               memmove(leaf->data + data_end + dsize,
+                       leaf->data + data_end,
+                       doff - data_end);
+               for (i = slot + 1; i < leaf->header.nritems; i++)
+                       leaf->items[i].offset += dsize;
+               memmove(leaf->items + slot, leaf->items + slot + 1,
+                       sizeof(struct item) *
+                       (leaf->header.nritems - slot - 1));
+       }
+       leaf->header.nritems -= 1;
+       if (leaf->header.nritems == 0) {
+               free(leaf);
+               del_ptr(root, &path, 1);
+       } else {
+               if (slot == 0)
+                       fixup_low_keys(&path, &leaf->items[0].key, 1);
+               if (leaf_space_used(leaf, 0, leaf->header.nritems) <
+                   LEAF_DATA_SIZE / 4) {
+                       /* push_leaf_left fixes the path.
+                        * make sure the path still points to our leaf
+                        * for possible call to del_ptr below
+                        */
+                       slot = path.slots[1];
+                       push_leaf_left(root, &path, 1);
+                       path.slots[1] = slot;
+                       if (leaf->header.nritems == 0) {
+                               free(leaf);
+                               del_ptr(root, &path, 1);
+                       }
+               }
+       }
+       return 0;
+}
+
+void print_leaf(struct leaf *l)
+{
+       int i;
+       int nr = l->header.nritems;
+       struct item *item;
+       printf("leaf %p total ptrs %d free space %d\n", l, nr,
+              leaf_free_space(l));
+       fflush(stdout);
+       for (i = 0 ; i < nr ; i++) {
+               item = l->items + i;
+               printf("\titem %d key (%lu %u %lu) itemoff %d itemsize %d\n",
+                       i,
+                       item->key.objectid, item->key.flags, item->key.offset,
+                       item->offset, item->size);
+               fflush(stdout);
+               printf("\t\titem data %.*s\n", item->size, l->data+item->offset);
+               fflush(stdout);
+       }
+}
+void print_tree(struct node *c)
+{
+       int i;
+       int nr;
+
+       if (!c)
+               return;
+       nr = c->header.nritems;
+       if (is_leaf(c->header.flags)) {
+               print_leaf((struct leaf *)c);
+               return;
+       }
+       printf("node %p level %d total ptrs %d free spc %lu\n", c,
+               node_level(c->header.flags), c->header.nritems,
+               NODEPTRS_PER_BLOCK - c->header.nritems);
+       fflush(stdout);
+       for (i = 0; i < nr; i++) {
+               printf("\tkey %d (%lu %u %lu) block %lx\n",
+                      i,
+                      c->keys[i].objectid, c->keys[i].flags, c->keys[i].offset,
+                      c->blockptrs[i]);
+               fflush(stdout);
+       }
+       for (i = 0; i < nr; i++) {
+               struct node *next = read_block(c->blockptrs[i]);
+               if (is_leaf(next->header.flags) &&
+                   node_level(c->header.flags) != 1)
+                       BUG();
+               if (node_level(next->header.flags) !=
+                       node_level(c->header.flags) - 1)
+                       BUG();
+               print_tree(next);
+       }
+
+}
+
+/* for testing only */
+int next_key(int i, int max_key) {
+       return rand() % max_key;
+       // return i;
+}
+
+int main() {
+       struct leaf *first_node = malloc(sizeof(struct leaf));
+       struct ctree_root root;
+       struct key ins;
+       char *buf;
+       int i;
+       int num;
+       int ret;
+       int run_size = 10000000;
+       int max_key = 100000000;
+       int tree_size = 0;
+       struct ctree_path path;
+
+
+       srand(55);
+       root.node = (struct node *)first_node;
+       memset(first_node, 0, sizeof(*first_node));
+       for (i = 0; i < run_size; i++) {
+               buf = malloc(64);
+               num = next_key(i, max_key);
+               // num = i;
+               sprintf(buf, "string-%d", num);
+               // printf("insert %d\n", num);
+               ins.objectid = num;
+               ins.offset = 0;
+               ins.flags = 0;
+               ret = insert_item(&root, &ins, buf, strlen(buf));
+               if (!ret)
+                       tree_size++;
+       }
+       srand(55);
+       for (i = 0; i < run_size; i++) {
+               num = next_key(i, max_key);
+               ins.objectid = num;
+               ins.offset = 0;
+               ins.flags = 0;
+               init_path(&path);
+               ret = search_slot(&root, &ins, &path);
+               if (ret) {
+                       print_tree(root.node);
+                       printf("unable to find %d\n", num);
+                       exit(1);
+               }
+       }
+       printf("node %p level %d total ptrs %d free spc %lu\n", root.node,
+               node_level(root.node->header.flags), root.node->header.nritems,
+               NODEPTRS_PER_BLOCK - root.node->header.nritems);
+       // print_tree(root.node);
+       printf("all searches good\n");
+       i = 0;
+       srand(55);
+       for (i = 0; i < run_size; i++) {
+               num = next_key(i, max_key);
+               ins.objectid = num;
+               del_item(&root, &ins);
+       }
+       print_tree(root.node);
+       return 0;
+}