Is there a particular reason that the label of a mounted XFS fileystem
can't be changed?
The man-page of xfs_admin gives a blanket "Devices that are mounted
cannot be modified" but no explanation for why that is.
In my case it's the label of the root-filesystem i want to change. So to
change it i would have to boot the computer with some kind of live or
rescure-system. Or i would need to temporarily connect the device to
another computer, both aren't really nice hoops to jump through just to
change a few characters.
The only thing i can compare this to is ext2 and with ext2 (/boot
partition, so it really is ext2) i can change the label to my hearts
content, even the device is mounted.
For my case i could live with it if i could remount the filesystem RO,
change the label and then having to reboot the machine, still nicer than
the other 2 options.