Red Hat Bugzilla – Bug 867412
libvirt fails to clear async job when p2p migration fails early
Last modified: 2013-02-21 02:10:28 EST
Description of problem: When p2p migration fails early because qemuMigrationIsAllowed or qemuMigrationIsSafe say migration should be cancelled, we fail to clear the migration-out async job. As a result of that, further APIs called for the same domain may fail with Timed out during operation: cannot acquire state change lock. Version-Release number of selected component (if applicable): libvirt-0.10.2-4.el6, introduced upstream in 0.9.5 How reproducible: 100% Steps to Reproduce: 1. create and start a domain with disk on NFS and cache != none 2. virsh migrate --p2p $URI $DOM 3. virsh migrate --p2p $URI $DOM Actual results: Step 2 correctly results in: error: Unsafe migration: Migration may lead to data corruption if disks use cache != none Steps 3 will timeout after 30 seconds and report: error: Timed out during operation: cannot acquire state change lock Expected results: No matter how many time we try to migrate the domain, it should still report error: Unsafe migration: Migration may lead to data corruption if disks use cache != none Additional info:
Patch sent upstream: https://www.redhat.com/archives/libvir-list/2012-October/msg00891.html
I can reproduce this with: libvirt-0.10.2-4.el6.x86_64 virsh # migrate aaa --p2p qemu+ssh://10.66.7.161/system --unsafe error: Timed out during operation: cannot acquire state change lock
Fixed upstream by v0.10.2-191-g837993d": commit 837993d845a32bb222959a84d1c03a0c47f785be Author: Jiri Denemark <jdenemar@redhat.com> Date: Wed Oct 17 14:08:17 2012 +0200 qemu: Clear async job when p2p migration fails early When p2p migration fails early because qemuMigrationIsAllowed or qemuMigrationIsSafe say migration should be cancelled, we fail to clear the migration-out async job. As a result of that, further APIs called for the same domain may fail with Timed out during operation: cannot acquire state change lock. Reported by Guido Winkelmann.
In POST: http://post-office.corp.redhat.com/archives/rhvirt-patches/2012-October/msg00920.html
Test with: # virsh dumpxml rhel63q ... <disk type='file' device='disk'> <driver name='qemu' type='qcow2' cache='writeback'/> <source file='/virt/rhel63q.img'/> <target dev='vda' bus='virtio'/> <alias name='virtio-disk0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/> </disk> ... # virsh migrate rhel63q --p2p qemu+ssh://10.66.7.161/system --unsafe and "default", "writethrough", "directsync" result are same. So it's verified.
correction： "default", "none", "writethrough", "writeback", and "unsafe" works well our qemu not support "directsync" yet.
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. http://rhn.redhat.com/errata/RHSA-2013-0276.html