Host: kernel 5.5.3, qemu-kvm, Btrfs, backing file is raw with +C 5.6. Guest: kernel 5.6.0-rc1, / is Btrfs Boot and login, and immediately run these commands: [root@localhost ~]# df -h /dev/vda4 96G 4.4G 91G 5% / # fstrim -v / /: 91 GiB (97633062912 bytes) trimmed 1 minute later [root@localhost ~]# fstrim -v / /: 3.5 GiB (3747549184 bytes) trimmed [root@localhost ~]# There's no activity happening in this one minute period. Reboot, and it's reproducible again. 91G trimmed the first time then 3.5G the second. Seems like new and unusual behavior. No kernel messages at all in either host or guest. -- Chris Murphy
