<snip>
This is intended. Otherwise it's an open avenue for the user to shoot
themselves in the foot.
I don't understand how?
If you know what you are doing and are
absolutely sure the original fs is no longer present
- then just flush
libblkid cache and you'll be able to set the FSID back to the original one.
<snip>
No no its not about the stale cache holding the original fsid. The use
case is - a golden copy of the bootable OS image is being used and
shares the same fsid on multiple hosts.
Now if you want to mount another copy it for some changes, you need to
btrfstune -m on the copy. And later if you want to boot it
successfully, it needs its original fsid back.
HTH, Anand
