Btrfs: Initial checkin, basic working tree code

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 810 insertions, 0 deletions

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
new file mode 100644
index 000000000000..893fd56960a0
--- /dev/null
+++ b/fs/btrfs/ctree.c
@@ -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;
+}