+
+truncate_racing:
+ vmtruncate(inode, inode->i_size);
+ balance_dirty_pages_ratelimited_nr(inode->i_mapping,
+ total_read);
+ goto out_unlock;
+}
+
+/*
+ * The back references tell us which tree holds a ref on a block,
+ * but it is possible for the tree root field in the reference to
+ * reflect the original root before a snapshot was made. In this
+ * case we should search through all the children of a given root
+ * to find potential holders of references on a block.
+ *
+ * Instead, we do something a little less fancy and just search
+ * all the roots for a given key/block combination.
+ */
+static int find_root_for_ref(struct btrfs_root *root,
+ struct btrfs_path *path,
+ struct btrfs_key *key0,
+ int level,
+ int file_key,
+ struct btrfs_root **found_root,
+ u64 bytenr)
+{
+ struct btrfs_key root_location;
+ struct btrfs_root *cur_root = *found_root;
+ struct btrfs_file_extent_item *file_extent;
+ u64 root_search_start = BTRFS_FS_TREE_OBJECTID;
+ u64 found_bytenr;
+ int ret;
+
+ root_location.offset = (u64)-1;
+ root_location.type = BTRFS_ROOT_ITEM_KEY;
+ path->lowest_level = level;
+ path->reada = 0;
+ while(1) {
+ ret = btrfs_search_slot(NULL, cur_root, key0, path, 0, 0);
+ found_bytenr = 0;
+ if (ret == 0 && file_key) {
+ struct extent_buffer *leaf = path->nodes[0];
+ file_extent = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_file_extent_item);
+ if (btrfs_file_extent_type(leaf, file_extent) ==
+ BTRFS_FILE_EXTENT_REG) {
+ found_bytenr =
+ btrfs_file_extent_disk_bytenr(leaf,
+ file_extent);
+ }
+ } else if (!file_key) {
+ if (path->nodes[level])
+ found_bytenr = path->nodes[level]->start;
+ }
+
+ btrfs_release_path(cur_root, path);
+
+ if (found_bytenr == bytenr) {
+ *found_root = cur_root;
+ ret = 0;
+ goto out;
+ }
+ ret = btrfs_search_root(root->fs_info->tree_root,
+ root_search_start, &root_search_start);
+ if (ret)
+ break;
+
+ root_location.objectid = root_search_start;
+ cur_root = btrfs_read_fs_root_no_name(root->fs_info,
+ &root_location);
+ if (!cur_root) {
+ ret = 1;
+ break;
+ }
+ }
+out:
+ path->lowest_level = 0;
+ return ret;