ext4_ext_try_to_merge
ext4_ext_try_to_merge(handle, inode, path, nearex);
ext4_ext_try_to_merge(handle, inode, path, ex);
ext4_ext_try_to_merge(handle, inode2, path2, ex2);
ext4_ext_try_to_merge(handle, inode1, path1, ex1);
ext4_ext_try_to_merge(NULL, inode, path, ex);