i've seen guest data corruption and qcow2 corruption on ext4. i've seen one case where the guest (win10) reports corruption but qemu- img check does not, but that's the outlier, usually both guest and qemu- img report corruption.
for me the issue seems to only be win10 guests using virtio-scsi, i've not seen it on any of 25+ linux/solaris/macos/win2019 guests no matter what device driver/cache/trim i use. current workaround is convert from qcow2 to raw, everything else stays the same and i have no issues. -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1847793 Title: qemu 4.1.0 - Corrupt guest filesystem after new vm install Status in QEMU: New Bug description: When I install a new vm with qemu 4.1.0 all the guest filesystems are corrupt. The first boot from the install dvd iso is ok and the installer work fine. But the guest system hangs after the installer finishes and I reboot the guest. I can see the grub boot menue but the system cannot load the initramfs. Testet with: - RedHat Enterprise Linux 7.5, 7.6 and 7.7 (RedHat uses xfs for the /boot and / partition) Guided install with the graphical installer, no lvm selected. - Debian Stable/Buster (Debian uses ext4 for / and /home partition) Guidet install with the graphical installer and default options. Used commandline to create the vm disk image: qemu-img create -f qcow2 /volumes/disk2-part2/vmdisks/vmtest10-1.qcow2 20G Used qemu commandline for vm installation: #!/bin/sh # vmtest10 Installation # /usr/bin/qemu-system-x86_64 -cpu SandyBridge-IBRS \ -soundhw hda \ -M q35 \ -k de \ -vga qxl \ -machine accel=kvm \ -m 4096 \ -display gtk \ -drive file=/volumes/disk2-part2/images/debian-10.0.0-amd64-DVD-1.iso,if=ide,media=cdrom \ -drive file=/volumes/disk2-part2/images/vmtest10-1.qcow2,if=virtio,media=disk,cache=writeback \ -boot once=d,menu=off \ -device virtio-net-pci,mac=52:54:00:2c:02:6c,netdev=vlan0 \ -netdev bridge,br=br0,id=vlan0 \ -rtc base=localtime \ -name "vmtest10" \ -usb -device usb-tablet \ -spice disable-ticketing \ -device virtio-serial-pci \ -device virtserialport,chardev=spicechannel0,name=com.redhat.spice.0 \ -chardev spicevmc,id=spicechannel0,name=vdagent $* Host OS: Archlinux (last updated at 10.10.2019) Linux testing 5.3.5-arch1-1-ARCH #1 SMP PREEMPT Mon Oct 7 19:03:08 UTC 2019 x86_64 GNU/Linux No libvirt in use. With qemu 4.0.0 it works fine without any errors. To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1847793/+subscriptions