[Qemu-devel] [PATCH RFC v2 0/6] COLO block replication supports shared disk case

[zhanghailiang]

COLO block replication doesn't support the shared disk case,
Here we try to implement it.

For the detail of shared-disk scenario, please refer to patch 1.

COLO codes with shared-disk block replication can be found from the link:
https://github.com/coloft/qemu/tree/colo-developing-with-shared-disk-2016-12-5

Test procedures:
1. Secondary:
# x86_64-softmmu/qemu-system-x86_64 -boot c -m 2048 -smp 2 -qmp stdio -vnc :9 
-name secondary -enable-kvm -cpu qemu64,+kvmclock -device piix3-usb-uhci -drive 
if=none,driver=qcow2,file.filename=/mnt/ramfs/hidden_disk.img,id=hidden_disk0,backing.driver=raw,backing.file.filename=/work/kvm/suse11_sp3_64
  -drive 
if=ide,id=active-disk0,driver=replication,mode=secondary,file.driver=qcow2,top-id=active-disk0,file.file.filename=/mnt/ramfs/active_disk.img,file.backing=hidden_disk0,shared-disk=on
 -incoming tcp:0:9999

Issue qmp commands:
{'execute':'qmp_capabilities'}
{'execute': 'nbd-server-start', 'arguments': {'addr': {'type': 'inet', 'data': 
{'host': '0', 'port': '9998'} } } }
{'execute': 'nbd-server-add', 'arguments': {'device': 'hidden_disk0', 
'writable': true } }

2.Primary:
# x86_64-softmmu/qemu-system-x86_64 -enable-kvm -m 2048 -smp 2 -qmp stdio -vnc 
:9 -name primary -cpu qemu64,+kvmclock -device piix3-usb-uhci -drive 
if=virtio,id=primary_disk0,file.filename=/work/kvm/suse11_sp3_64,driver=raw -S

Issue qmp commands:
{'execute':'qmp_capabilities'}
{'execute': 'human-monitor-command', 'arguments': {'command-line': 'drive_add 
-n buddy 
driver=replication,mode=primary,file.driver=nbd,file.host=9.42.3.17,file.port=9998,file.export=hidden_disk0,shared-disk-id=primary_disk0,shared-disk=on,node-name=rep'}}
{'execute': 'migrate-set-capabilities', 'arguments': {'capabilities': [ 
{'capability': 'x-colo', 'state': true } ] } }
{'execute': 'migrate', 'arguments': {'uri': 'tcp:9.42.3.17:9999' } }

3. Failover
Secondary side:
Issue qmp commands:
{ 'execute': 'nbd-server-stop' }
{ "execute": "x-colo-lost-heartbeat" }

Please review and any commits are welcomed.

Cc: Juan Quintela <address@hidden>
Cc: Amit Shah <address@hidden> 
Cc: Dr. David Alan Gilbert (git) <address@hidden>
Cc: address@hidden

v2:
- Drop the patch which add a blk_root() helper
- Fix some comments from Changlong

zhanghailiang (6):
  docs/block-replication: Add description for shared-disk case
  replication: add shared-disk and shared-disk-id options
  replication: Split out backup_do_checkpoint() from
    secondary_do_checkpoint()
  replication: fix code logic with the new shared_disk option
  replication: Implement block replication for shared disk case
  nbd/replication: implement .bdrv_get_info() for nbd and replication
    driver

 block/nbd.c                |  12 ++++
 block/replication.c        | 156 +++++++++++++++++++++++++++++++++++----------
 docs/block-replication.txt | 139 ++++++++++++++++++++++++++++++++++++++--
 qapi/block-core.json       |   9 ++-
 4 files changed, 278 insertions(+), 38 deletions(-)

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1.8.3.1