Comment # 6 on bug 1032027 from Holger Hees

for me, the same happens with Leap 15 and kernel 4.12.14-lp150.12.7-default

from time to time if I wake up my laptop, the system is completely unresponsive
for several minutes until the btrfs process is done.

my system is a i7-7700HQ, 16GB Memory and a 512GB SSD