On 10.10.19 17:17, Max Reitz wrote: > Hi everyone, > > (CCs just based on tags in the commit in question) > > I have two bug reports which claim problems of qcow2 on XFS on ppc64le > machines since qemu 4.1.0. One of those is about bad performance > (sorry, is isn’t public :-/), the other about data corruption > (https://bugzilla.redhat.com/show_bug.cgi?id=1751934). > > It looks like in both cases reverting c8bb23cbdbe3 solves the problem > (which optimized COW of unallocated areas). > > I think I’ve looked at every angle but can‘t find what could be wrong > with it. Do any of you have any idea? :-/
I now have a reproducer with CentOS, so it’s actually useful outside of Red Hat: $ cd $TEST_DIR (Download CentOS-8-x86_64-1905-dvd1.iso here, e.g. from http://mirror1.hs-esslingen.de/pub/Mirrors/centos/8.0.1905/isos/x86_64/CentOS-8-x86_64-1905-dvd1.torrent ) $ wget http://mirror1.hs-esslingen.de/pub/Mirrors/centos/8.0.1905/BaseOS/x86_64/os/isolinux/vmlinuz $ wget http://mirror1.hs-esslingen.de/pub/Mirrors/centos/8.0.1905/BaseOS/x86_64/os/isolinux/initrd.img $ mkdir ks $ cat > ks/ks.cfg <<EOF rootpw 123456 install keyboard us lang en_US.UTF-8 rootpw 123456 zerombr autopart clearpart --all --initlabel %packages --default @core %end EOF $ $QEMU_BUILD_DIR/qemu-img create -f qcow2 disk.qcow2 30G $ $QEMU_BUILD_DIR/x86_64-softmmu/qemu-system-x86_64 \ -name 'centos' \ -machine pc \ -nodefaults \ -vga std \ -display gtk \ -serial stdio \ -device virtio-scsi-pci,id=virtio_scsi_pci0,bus=pci.0 \ -blockdev "{'node-name': 'target-disk', 'driver': 'qcow2', 'file': { 'driver': 'file', 'filename': 'disk.qcow2', 'cache': { 'direct': true }, 'aio': 'native' } }" \ -device scsi-hd,id=image1,drive=target-disk \ -blockdev \ file,node-name=install-cd,filename=CentOS-8-x86_64-1905-dvd1.iso \ -device scsi-cd,drive=install-cd \ -blockdev vvfat,node-name=kscfg,dir=ks,label=OEMDRV,read-only=on \ -device scsi-hd,drive=kscfg \ -kernel vmlinuz \ -append 'ks=hd:LABEL=OEMDRV:/ks.cfg delay=60 console=ttyS0' \ -initrd initrd.img \ -boot order=cd,menu=off,strict=off \ -m 2048 \ -enable-kvm This installation fails about 50/50 for me. To retry, just run the last two steps (qemu-img create and the installation itself). Max
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