[Bug 1881231] Re: colo: Can not recover colo after svm failover twice

[ye.zou]

primary vm command:
./qemu-system-x86_64 -L /usr/share/qemu-kvm/ -enable-kvm -cpu qemu64,+kvmclock 
-m 2048 -smp 2 -qmp stdio -vnc :0 -device piix3-usb-uhci -device usb-tablet 
-name primary -netdev 
tap,id=hn0,vhost=off,br=br_bond1,helper=/usr/libexec/qemu-bridge-helper -device 
rtl8139,id=e0,netdev=hn0,romfile="" -chardev 
socket,id=mirror0,host=169.254.66.11,port=9003,server,nowait -chardev 
socket,id=compare1,host=169.254.66.11,port=9004,server,wait -chardev 
socket,id=compare0,host=169.254.66.11,port=9001,server,nowait -chardev 
socket,id=compare0-0,host=169.254.66.11,port=9001 -chardev 
socket,id=compare_out,host=169.254.66.11,port=9005,server,nowait -chardev 
socket,id=compare_out0,host=169.254.66.11,port=9005 -object 
filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 -object 
filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out -object 
filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 -object 
iothread,id=iothread1 -object 
colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1
 -drive 
if=ide,id=colo-disk0,driver=quorum,read-pattern=fifo,vote-threshold=1,children.0.file.filename=/root/Centos7.4.qcow2,children.0.driver=qcow2
 -S

secondary vm:
./qemu-system-x86_64 -L /usr/share/qemu-kvm/ -enable-kvm -cpu qemu64,+kvmclock 
-m 2048 -smp 2 -qmp stdio -vnc :1 -device piix3-usb-uhci -device usb-tablet 
-name secondary -netdev 
tap,id=hn0,vhost=off,br=br_bond1,helper=/usr/libexec/qemu-bridge-helper -device 
rtl8139,id=e0,netdev=hn0,romfile="" -chardev 
socket,id=red0,host=169.254.66.11,port=9003,reconnect=1 -chardev 
socket,id=red1,host=169.254.66.11,port=9004,reconnect=1 -object 
filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 
filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 
filter-rewriter,id=rew0,netdev=hn0,queue=all -drive 
if=none,id=parent0,file.filename=/root/Centos7.4.qcow2,driver=qcow2 -drive 
if=none,id=childs0,driver=replication,mode=secondary,file.driver=qcow2,top-id=childs0,file.file.filename=/root/active.qcow2,file.backing.driver=qcow2,file.backing.file.filename=/root/hidden.qcow2,file.backing.backing=parent0
 -drive 
if=none,id=colo-disk0,driver=quorum,read-pattern=fifo,vote-threshold=1,children.0=childs0
 -incoming tcp:0:9998

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1881231

Title:
  colo: Can not  recover colo after svm failover twice

Status in QEMU:
  New

Bug description:
  Hi Expert,
  x-blockdev-change met some error, during testing colo

  Host os:
  CentOS Linux release 7.6.1810 (Core)

  Reproduce steps:
  1. create colo vm following 
https://github.com/qemu/qemu/blob/master/docs/COLO-FT.txt
  2. kill secondary vm and remove the nbd child from the quorum to wait for 
recover
    type those commands on primary vm console:
    { 'execute': 'x-blockdev-change', 'arguments': {'parent': 'colo-disk0', 
'child': 'children.1'}}
    { 'execute': 'human-monitor-command','arguments': {'command-line': 
'drive_del replication0'}}
    { 'execute': 'x-colo-lost-heartbeat'}
  3. recover colo
  4. kill secondary vm again after recover colo and type same commands as step 
2:
    { 'execute': 'x-blockdev-change', 'arguments': {'parent': 'colo-disk0', 
'child': 'children.1'}}
    { 'execute': 'human-monitor-command','arguments': {'command-line': 
'drive_del replication0'}}
    { 'execute': 'x-colo-lost-heartbeat'}
    but the first command got error
    { 'execute': 'x-blockdev-change', 'arguments': {'parent': 'colo-disk0', 
'child': 'children.1'}}
  {"error": {"class": "GenericError", "desc": "Node 'colo-disk0' does not have 
child 'children.1'"}}

  according to https://www.qemu.org/docs/master/qemu-qmp-ref.html
  Command: x-blockdev-change
  Dynamically reconfigure the block driver state graph. It can be used to add, 
remove, insert or replace a graph node. Currently only the Quorum driver 
implements this feature to add or remove its child. This is useful to fix a 
broken quorum child.

  It seems x-blockdev-change not worked as expected.

  Thanks.

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1881231/+subscriptions