BTRFS_EXTENT_FLAG_ALLOCATED
uint64 flags = node->flags & (~BTRFS_EXTENT_FLAG_ALLOCATED);
if ((flags & BTRFS_EXTENT_FLAG_ALLOCATED) != 0)
return (flags & BTRFS_EXTENT_FLAG_ALLOCATED) != 0;
flags |= BTRFS_EXTENT_FLAG_ALLOCATED;
type | BTRFS_EXTENT_FLAG_ALLOCATED);