return ret;
 }
 
-int commit_transaction(struct ctree_root *root)
+int commit_transaction(struct ctree_root *root, struct ctree_super_block *s)
 {
-       int ret;
+       int ret = 0;
+
        ret = __commit_transaction(root);
        if (!ret && root != root->extent_root)
                ret = __commit_transaction(root->extent_root);
        BUG_ON(ret);
+       if (root->commit_root != root->node) {
+               struct tree_buffer *snap = root->commit_root;
+               root->commit_root = root->node;
+               root->node->count++;
+               ret = btrfs_drop_snapshot(root, snap);
+               BUG_ON(ret);
+               tree_block_release(root, snap);
+       }
+        write_ctree_super(root, s);
+       btrfs_finish_extent_commit(root);
        return ret;
 }
 
 {
        INIT_LIST_HEAD(&root->trans);
        INIT_LIST_HEAD(&root->cache);
+       root->cache_size = 0;
        root->fp = fp;
        root->node = NULL;
-       root->node = read_tree_block(root, info->tree_root);
        root->extent_root = extent_root;
+       root->commit_root = NULL;
+       root->node = read_tree_block(root, info->tree_root);
+       memset(&root->current_insert, 0, sizeof(root->current_insert));
        return 0;
 }
 
                return NULL;
        }
        INIT_RADIX_TREE(&root->cache_radix, GFP_KERNEL);
+       INIT_RADIX_TREE(&root->pinned_radix, GFP_KERNEL);
+       INIT_RADIX_TREE(&extent_root->pinned_radix, GFP_KERNEL);
        INIT_RADIX_TREE(&extent_root->cache_radix, GFP_KERNEL);
        ret = pread(fp, super, sizeof(struct ctree_super_block),
                     CTREE_SUPER_INFO_OFFSET(CTREE_BLOCKSIZE));
        BUG_ON(ret < 0);
        __setup_root(root, extent_root, &super->root_info, fp);
        __setup_root(extent_root, extent_root, &super->extent_info, fp);
+       root->commit_root = root->node;
+       root->node->count++;
        return root;
 }
 
        }
        return 0;
 }
-int close_ctree(struct ctree_root *root)
+int close_ctree(struct ctree_root *root, struct ctree_super_block *s)
 {
-       commit_transaction(root);
+       commit_transaction(root, s);
+       __commit_transaction(root->extent_root);
+       write_ctree_super(root, s);
        drop_cache(root->extent_root);
        drop_cache(root);
        BUG_ON(!list_empty(&root->trans));
                tree_block_release(root, root->node);
        if (root->extent_root->node)
                tree_block_release(root->extent_root, root->extent_root->node);
+       tree_block_release(root, root->commit_root);
        free(root);
        printf("on close %d blocks are allocated\n", allocated_blocks);
        return 0;
 
  * other allocations are done.  The pending tag is also used in the same
  * manner for deletes.
  */
-#define CTREE_EXTENT_PENDING 0
+#define CTREE_EXTENT_PENDING_ADD 0
+#define CTREE_EXTENT_PENDING_DEL 1
 
 static int inc_block_ref(struct ctree_root *root, u64 blocknr)
 {
        key.flags = 0;
        key.offset = 1;
        ret = search_slot(root->extent_root, &key, &path, 0, 1);
+       if (ret != 0)
+               BUG();
        BUG_ON(ret != 0);
        l = &path.nodes[0]->leaf;
        item = (struct extent_item *)(l->data +
                                      l->items[path.slots[0]].offset);
        item->refs++;
+
        BUG_ON(list_empty(&path.nodes[0]->dirty));
        release_path(root->extent_root, &path);
        return 0;
 }
 
+static int lookup_block_ref(struct ctree_root *root, u64 blocknr, int *refs)
+{
+       struct ctree_path path;
+       int ret;
+       struct key key;
+       struct leaf *l;
+       struct extent_item *item;
+       init_path(&path);
+       key.objectid = blocknr;
+       key.flags = 0;
+       key.offset = 1;
+       ret = search_slot(root->extent_root, &key, &path, 0, 0);
+       if (ret != 0)
+               BUG();
+       l = &path.nodes[0]->leaf;
+       item = (struct extent_item *)(l->data +
+                                     l->items[path.slots[0]].offset);
+       *refs = item->refs;
+       release_path(root->extent_root, &path);
+       return 0;
+}
+
 int btrfs_inc_ref(struct ctree_root *root, struct tree_buffer *buf)
 {
        u64 blocknr;
        int i;
+
+       if (root == root->extent_root)
+               return 0;
+       if (is_leaf(buf->node.header.flags))
+               return 0;
+
        for (i = 0; i < buf->node.header.nritems; i++) {
                blocknr = buf->node.blockptrs[i];
                inc_block_ref(root, blocknr);
        return 0;
 }
 
+int btrfs_finish_extent_commit(struct ctree_root *root)
+{
+       struct ctree_root *extent_root = root->extent_root;
+       unsigned long gang[8];
+       int ret;
+       int i;
+
+       while(1) {
+               ret = radix_tree_gang_lookup(&extent_root->pinned_radix,
+                                                (void **)gang, 0,
+                                                ARRAY_SIZE(gang));
+               if (!ret)
+                       break;
+               for (i = 0; i < ret; i++)
+                       radix_tree_delete(&extent_root->pinned_radix, gang[i]);
+       }
+       return 0;
+}
+
 /*
- * find all the blocks marked as pending in the radix tree and remove
- * them from the extent map
+ * remove an extent from the root, returns 0 on success
  */
-static int del_pending_extents(struct ctree_root *extent_root)
+int __free_extent(struct ctree_root *root, u64 blocknr, u64 num_blocks)
+{
+       struct ctree_path path;
+       struct key key;
+       struct ctree_root *extent_root = root->extent_root;
+       int ret;
+       struct item *item;
+       struct extent_item *ei;
+       key.objectid = blocknr;
+       key.flags = 0;
+       key.offset = num_blocks;
+
+       init_path(&path);
+       ret = search_slot(extent_root, &key, &path, -1, 1);
+       if (ret) {
+               printf("failed to find %Lu\n", key.objectid);
+               print_tree(extent_root, extent_root->node);
+               printf("failed to find %Lu\n", key.objectid);
+               BUG();
+       }
+       item = path.nodes[0]->leaf.items + path.slots[0];
+       ei = (struct extent_item *)(path.nodes[0]->leaf.data + item->offset);
+       BUG_ON(ei->refs == 0);
+       ei->refs--;
+       if (ei->refs == 0) {
+               if (root == extent_root) {
+                       int err;
+                       radix_tree_preload(GFP_KERNEL);
+                       err = radix_tree_insert(&extent_root->pinned_radix,
+                                         blocknr, (void *)blocknr);
+                       BUG_ON(err);
+                       radix_tree_preload_end();
+               }
+               ret = del_item(extent_root, &path);
+               if (ret)
+                       BUG();
+       }
+       release_path(extent_root, &path);
+       return ret;
+}
+
+/*
+ * insert all of the pending extents reserved during the original
+ * allocation.  (CTREE_EXTENT_PENDING).  Returns zero if it all worked out
+ */
+static int insert_pending_extents(struct ctree_root *extent_root)
 {
        int ret;
        struct key key;
+       struct extent_item item;
        struct tree_buffer *gang[4];
        int i;
-       struct ctree_path path;
 
+       // FIXME -ENOSPC
+       item.owner = extent_root->node->node.header.parentid;
+       item.refs = 1;
        while(1) {
                ret = radix_tree_gang_lookup_tag(&extent_root->cache_radix,
                                                 (void **)gang, 0,
                                                 ARRAY_SIZE(gang),
-                                                CTREE_EXTENT_PENDING);
+                                                CTREE_EXTENT_PENDING_ADD);
                if (!ret)
                        break;
                for (i = 0; i < ret; i++) {
                        key.objectid = gang[i]->blocknr;
                        key.flags = 0;
                        key.offset = 1;
-                       init_path(&path);
-                       ret = search_slot(extent_root, &key, &path, -1, 1);
+                       ret = insert_item(extent_root, &key, &item,
+                                         sizeof(item));
                        if (ret) {
+                               printf("%Lu already in tree\n", key.objectid);
                                print_tree(extent_root, extent_root->node);
-                               printf("unable to find %Lu\n", key.objectid);
                                BUG();
                                // FIXME undo it and return sane
                                return ret;
                        }
-                       ret = del_item(extent_root, &path);
-                       if (ret) {
-                               BUG();
-                               return ret;
-                       }
-                       release_path(extent_root, &path);
+                       radix_tree_tag_clear(&extent_root->cache_radix,
+                                            gang[i]->blocknr,
+                                            CTREE_EXTENT_PENDING_ADD);
+                       tree_block_release(extent_root, gang[i]);
+               }
+       }
+       return 0;
+}
+
+/*
+ * find all the blocks marked as pending in the radix tree and remove
+ * them from the extent map
+ */
+static int del_pending_extents(struct ctree_root *extent_root)
+{
+       int ret;
+       struct tree_buffer *gang[4];
+       int i;
+
+       while(1) {
+               ret = radix_tree_gang_lookup_tag(&extent_root->cache_radix,
+                                                (void **)gang, 0,
+                                                ARRAY_SIZE(gang),
+                                                CTREE_EXTENT_PENDING_DEL);
+               if (!ret)
+                       break;
+               for (i = 0; i < ret; i++) {
+                       ret = __free_extent(extent_root, gang[i]->blocknr, 1);
                        radix_tree_tag_clear(&extent_root->cache_radix,
                                                gang[i]->blocknr,
-                                               CTREE_EXTENT_PENDING);
+                                               CTREE_EXTENT_PENDING_DEL);
                        tree_block_release(extent_root, gang[i]);
                }
        }
        return 0;
 }
 
+static int run_pending(struct ctree_root *extent_root)
+{
+       while(radix_tree_tagged(&extent_root->cache_radix,
+                               CTREE_EXTENT_PENDING_DEL) ||
+             radix_tree_tagged(&extent_root->cache_radix,
+                               CTREE_EXTENT_PENDING_ADD)) {
+               insert_pending_extents(extent_root);
+               del_pending_extents(extent_root);
+       }
+       return 0;
+}
+
+
 /*
  * remove an extent from the root, returns 0 on success
  */
 int free_extent(struct ctree_root *root, u64 blocknr, u64 num_blocks)
 {
-       struct ctree_path path;
        struct key key;
        struct ctree_root *extent_root = root->extent_root;
        struct tree_buffer *t;
        int pending_ret;
        int ret;
-       key.objectid = blocknr;
-       key.flags = 0;
-       key.offset = num_blocks;
+
        if (root == extent_root) {
-               t = read_tree_block(root, key.objectid);
-               radix_tree_tag_set(&root->cache_radix, key.objectid,
-                                  CTREE_EXTENT_PENDING);
+               t = find_tree_block(root, blocknr);
+               if (radix_tree_tag_get(&root->cache_radix, blocknr,
+                                     CTREE_EXTENT_PENDING_ADD)) {
+                       radix_tree_tag_clear(&root->cache_radix,
+                                            blocknr,
+                                            CTREE_EXTENT_PENDING_ADD);
+                       /* once for us */
+                       tree_block_release(root, t);
+                       /* once for the pending add */
+                       tree_block_release(root, t);
+               } else {
+                       radix_tree_tag_set(&root->cache_radix, blocknr,
+                                  CTREE_EXTENT_PENDING_DEL);
+               }
                return 0;
        }
-       init_path(&path);
-       ret = search_slot(extent_root, &key, &path, -1, 1);
-       if (ret) {
-               print_tree(extent_root, extent_root->node);
-               printf("failed to find %Lu\n", key.objectid);
-               BUG();
-       }
-       ret = del_item(extent_root, &path);
-       if (ret)
-               BUG();
-       release_path(extent_root, &path);
-       pending_ret = del_pending_extents(root->extent_root);
+       key.objectid = blocknr;
+       key.flags = 0;
+       key.offset = num_blocks;
+       ret = __free_extent(root, blocknr, num_blocks);
+       pending_ret = run_pending(root->extent_root);
        return ret ? ret : pending_ret;
 }
 
         */
        release_path(root, &path);
        BUG_ON(ins->objectid < search_start);
-       if (orig_root->extent_root == orig_root) {
+       if (1 || orig_root->extent_root == orig_root) {
                BUG_ON(num_blocks != 1);
                if ((root->current_insert.objectid <= ins->objectid &&
                    root->current_insert.objectid +
                   (root->current_insert.objectid > ins->objectid &&
                    root->current_insert.objectid <= ins->objectid +
                    ins->offset) ||
+                  radix_tree_lookup(&root->pinned_radix, ins->objectid) ||
                   radix_tree_tag_get(&root->cache_radix, ins->objectid,
-                                     CTREE_EXTENT_PENDING)) {
+                                     CTREE_EXTENT_PENDING_ADD)) {
                        search_start = ins->objectid + 1;
                        goto check_failed;
                }
        return ret;
 }
 
-/*
- * insert all of the pending extents reserved during the original
- * allocation.  (CTREE_EXTENT_PENDING).  Returns zero if it all worked out
- */
-static int insert_pending_extents(struct ctree_root *extent_root)
-{
-       int ret;
-       struct key key;
-       struct extent_item item;
-       struct tree_buffer *gang[4];
-       int i;
-
-       // FIXME -ENOSPC
-       item.refs = 1;
-       item.owner = extent_root->node->node.header.parentid;
-       while(1) {
-               ret = radix_tree_gang_lookup_tag(&extent_root->cache_radix,
-                                                (void **)gang, 0,
-                                                ARRAY_SIZE(gang),
-                                                CTREE_EXTENT_PENDING);
-               if (!ret)
-                       break;
-               for (i = 0; i < ret; i++) {
-                       key.objectid = gang[i]->blocknr;
-                       key.flags = 0;
-                       key.offset = 1;
-                       ret = insert_item(extent_root, &key, &item,
-                                         sizeof(item));
-                       if (ret) {
-                               printf("%Lu already in tree\n", key.objectid);
-                               print_tree(extent_root, extent_root->node);
-                               BUG();
-                               // FIXME undo it and return sane
-                               return ret;
-                       }
-                       radix_tree_tag_clear(&extent_root->cache_radix,
-                                            gang[i]->blocknr,
-                                            CTREE_EXTENT_PENDING);
-                       printf("%Lu is not pending\n", gang[i]->blocknr);
-                       tree_block_release(extent_root, gang[i]);
-               }
-       }
-       return 0;
-}
-
 /*
  * finds a free extent and does all the dirty work required for allocation
  * returns the key for the extent through ins, and a tree buffer for
                                  sizeof(extent_item));
                memset(&root->extent_root->current_insert, 0,
                       sizeof(struct key));
-               pending_ret = insert_pending_extents(root->extent_root);
+               pending_ret = run_pending(root->extent_root);
                if (ret)
                        return ret;
                if (pending_ret)
        BUG_ON(ins->offset != 1);
        *buf = find_tree_block(root, ins->objectid);
        BUG_ON(!*buf);
-       printf("%Lu is pending\n", ins->objectid);
        radix_tree_tag_set(&root->cache_radix, ins->objectid,
-                          CTREE_EXTENT_PENDING);
+                          CTREE_EXTENT_PENDING_ADD);
        (*buf)->count++;
        dirty_tree_block(root, *buf);
        return 0;
        ret = alloc_extent(root, 1, 0, (unsigned long)-1,
                           root->node->node.header.parentid,
                           &ins, &buf);
-
        if (ret) {
                BUG();
                return NULL;
        }
        if (root != root->extent_root)
                BUG_ON(radix_tree_tag_get(&root->extent_root->cache_radix,
-                                         buf->blocknr, CTREE_EXTENT_PENDING));
+                                         buf->blocknr,
+                                         CTREE_EXTENT_PENDING_ADD));
        return buf;
 }
+
+int btrfs_drop_snapshot(struct ctree_root *root, struct tree_buffer *snap)
+{
+       int ret;
+       int level;
+       int refs;
+       u64 blocknr = snap->blocknr;
+
+       level = node_level(snap->node.header.flags);
+       ret = lookup_block_ref(root, snap->blocknr, &refs);
+       BUG_ON(ret);
+       if (refs == 1 && level != 0) {
+               struct node *n = &snap->node;
+               struct tree_buffer *b;
+               int i;
+               for (i = 0; i < n->header.nritems; i++) {
+                       b = read_tree_block(root, n->blockptrs[i]);
+                       /* FIXME, don't recurse here */
+                       ret = btrfs_drop_snapshot(root, b);
+                       BUG_ON(ret);
+                       tree_block_release(root, b);
+               }
+       }
+       ret = free_extent(root, blocknr, 1);
+       BUG_ON(ret);
+       return 0;
+}
+