(This is similar/related to #2528)

The change in 602c1c5 broke internal-only remounting of FUSE filesystems.

I stumbled across this as ceph-fuse stopped working on machines having util-linux 2.39 installed.

The mount looks like this:

ceph-fuse on /ceph type fuse.ceph-fuse (rw,nosuid,nodev,relatime,user_id=0,group_id=0,allow_other)

While trying to remount, this results failures of either:

• fsconfig(name=allow_other,value=(null))
• fsconfig(name=user_id,value=0)

I also tried this with a FUSE mount of a borg repository, which fails the same way. That's why I think it will affect all fuse mounts.

v2.38 (or even just c15b21c) work fine in this case, so I assume this is a regression.