Readonly mode breaks some assumptions that live restore makes about regular files. Live restore will attempt to atomically copy those files on open, if they don't exist.

This is a write operation to the destination and not legal in readonly mode. Working around this is relatively trivial but it changes a lot of the assumed semantics around the live restore file handle.

Thus the changes to support read only mode will likely propagate a bit throughout the live_restore_fs.c file. Additionally the server must avoid creating background threads in readonly mode but that is a trivial change.

Scope:

• Support live restore running in readonly mode