Red Hat Bugzilla – Bug 1515604
qemu-img info: failed to get "consistent read" lock on a mirroring image
Last modified: 2018-04-10 20:51:20 EDT
Description of problem: As subject Version-Release number of selected component (if applicable): qemu-kvm-rhev-2.10.0-6.el7.x86_64 How reproducible: 100% Steps to Reproduce: Create this bug to track an upstream issue discussion: http://lists.nongnu.org/archive/html/qemu-discuss/2017-11/msg00045.html # /usr/libexec/qemu-kvm -name A -machine pc,accel=kvm \ -vnc 0.0.0.0:1 \ -monitor stdio \ -qmp tcp:0:5555,server,nowait \ -serial unix:/tmp/monitor,server,nowait \ -drive file=/var/lib/libvirt/images/V.qcow2,format=qcow2,if=none,id=drive-virtio-blk0,werror=stop,rerror=stop \ -device virtio-blk-pci,drive=drive-virtio-blk0,id=virtio-blk0 QEMU 2.10.0 monitor - type 'help' for more information (qemu) drive_mirror drive-virtio-blk0 /var/lib/libvirt/images/V.new Formatting '/var/lib/libvirt/images/V.new', fmt=qcow2 size=10737418240 cluster_size=65536 lazy_refcounts=off refcount_bits=16 # qemu-img info /var/lib/libvirt/images/V.new -U qemu-img: Could not open '/var/lib/libvirt/images/V.new': Failed to get "consistent read" lock Is another process using the image? Actual results: As above Expected results: Could query image info on mirroring image by -U option. Additional info:
Fix is on the mailing list: [PATCH for-2.11 0/2] Fix 'qemu-img info' on mirror target https://lists.gnu.org/archive/html/qemu-block/2017-11/msg00796.html
Turns out this fixed only raw images, but not image formats. Sent a follow-up: [PATCH] block: Formats don't need CONSISTENT_READ with NO_IO http://lists.gnu.org/archive/html/qemu-block/2017-11/msg01191.html
Fix included in qemu-kvm-rhev-2.10.0-17.el7
Reproduced on qemu-kvm-rhev-10:2.10.0-14.el7.x86_64: Steps: 1. Launch guest: /usr/libexec/qemu-kvm \ -name A \ -machine pc,accel=kvm \ -monitor stdio \ -drive file=/home/kvm_autotest_root/images/rhel74-64-virtio.qcow2,format=qcow2,if=none,id=drive-virtio-blk0,werror=stop,rerror=stop \ -device virtio-blk-pci,drive=drive-virtio-blk0,id=virtio-blk0 2. Block mirror: (qemu) drive_mirror drive-virtio-blk0 mirror 3. # qemu-img info -U mirror Results: Can't get image information. # qemu-img info -U mirror qemu-img: Could not open 'mirror': Failed to get "consistent read" lock Is another process using the image? Verified on qemu-kvm-rhev-2.10.0-17.el7.x86_64: Steps same as above. Results: Get image information correctly. # qemu-img info -U mirror image: mirror file format: qcow2 virtual size: 20G (21474836480 bytes) disk size: 1.9G cluster_size: 65536 Format specific information: compat: 1.1 lazy refcounts: false refcount bits: 16 corrupt: false Moving to VERIFIED.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHSA-2018:1104