In your example, the disk is entirely read-only I think.
I would guess the state of each disk replica (HEALTHY, UNHEALTHY) is stored in a master elected data store. Anytime a write to one replica fails, the data store must be updated to change the state of the failed replica before considering the write complete.
Then to change the state back to HEALTHY, everything must be online and fully re-replicated.
If the master elected state store can't be written to, because (due to a network split) it doesn't have sufficient votes to gain mastership, then no writes can occur.
I would guess the state of each disk replica (HEALTHY, UNHEALTHY) is stored in a master elected data store. Anytime a write to one replica fails, the data store must be updated to change the state of the failed replica before considering the write complete.
Then to change the state back to HEALTHY, everything must be online and fully re-replicated.
If the master elected state store can't be written to, because (due to a network split) it doesn't have sufficient votes to gain mastership, then no writes can occur.