Is it permissible to fast the six days of Shawwal and the day of Ashura for someone who has to make up missed days from Ramadan?

The jurists differed on the ruling of voluntary fasting before making up for Ramadan. The majority (Hanafis, Malikis, and Shafi'is) held that it is permissible, but the Hanafis consider it permissible without being disliked (makruh), while the Malikis and Shafi'is say it is permissible but disliked. Their evidence is that making up (qada') is not obligatory immediately. On the other hand, the Hanbalis went to the extent of prohibiting it and considering it invalid, basing their argument on a hadith that is not sound due to its inconsistency (idtirab) and weak chain of transmission (isnad). There is another narration from Imam Ahmad that permits voluntary fasting before making up. The most preponderant view is that of the majority, so there is no harm in observing voluntary fasts, such as the six days (of Shawwal) or the day of Ashura, before making up for Ramadan, because the time for making up Ramadan is expansive, whereas the time for voluntary fasting is restricted and cannot be regained if missed.