The code of mb_find_order_for_block is a bit obscure, but we can
simplify it with mb_find_buddy(), make the code more concise.
Signed-off-by: NChunguang Xu <brookxu@tencent.com>
Reviewed-by: NAndreas Dilger <adilger@dilger.ca>
Link: https://lore.kernel.org/r/1604764698-4269-3-git-send-email-brookxu@tencent.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>