Hi,
On my thinlpad T440p, i am running out of disk space, and earlier, I set up swap to be 16G (because I had 16G Ram and erroneously thought it would help).
I tried to reduce it to 8G. I followed some instructions from StackOverflow - and was able to turn swapoff.
the next command did not work, and also the swapon also failed.
I thought a restart would reset the problem but then it now hangs.
More information really is needed... There are many possibilities depending on if you gave any commands that changed partitions - and if you changed a partition while it was mounted.
You can find and review the exact commands youi used by launching terminal and typing
history
then go through and find the commands you used. If you recall the date well enough, you can insert a date replacing the symbols here: