Chuck Anderson
2010-Dec-29 19:55 UTC
[Xen-devel] hotplugStatusCallback 5 (device busy) error during local live migration
The following error shows up in xend.log while doing a local live migration of a 2.6.32 based PV guest running on a Xen 3.4.0 based system: [2010-12-28 09:00:51 4826] DEBUG (DevController:144) Waiting for 51728. [2010-12-28 09:00:51 4826] DEBUG (DevController:629) hotplugStatusCallback /local/domain/0/backend/vbd/5696/51728/hotplug-status. [2010-12-28 09:00:51 4826] DEBUG (DevController:643) hotplugStatusCallback 5. [2010-12-28 09:00:51 4826] ERROR (XendCheckpoint:347) Device 51728 (vbd) could not be connected. This message shows up in the domU''s dmesg: vbd vbd-51728: 16 Device in use; refusing to close vm.cfg has: disk = [''file:/OVS/seed_pool/OVM_EL5U5_X86_64_PVM_10GB/System.img,xvda,w'',''phy:/dev/sda1,xvdb,w''] The messages do not occur after changing "w" to "w+" (may have been "w!"). Is "w+" required for local migrations? Is it masking an underlying bug? waitForBackend() calls hotplugStatusCallback(): xen/source/tools/python/xen/xend/server/DevController.py waitForBackend() calls hotplugStatusCallback() 556 xswatch(statusPath, hotplugStatusCallback, ev, result) 557 558 ev.wait(DEVICE_CREATE_TIMEOUT) xen/source/tools/python/xen/xend/server/DevController.py hotplugStatusCallback() 633 if status is not None: 634 if status == HOTPLUG_STATUS_ERROR: 635 result[''status''] = Error 636 elif status == HOTPLUG_STATUS_BUSY: 637 result[''status''] = Busy 638 else: 639 result[''status''] = Connected 640 else: 641 return 1 This treats HOTPLUG_STATUS_BUSY as a one-time error. It seems like it should return 1 (keep watching) on HOTPLUG_STATUS_BUSY, something like: if status is not None: if status == HOTPLUG_STATUS_ERROR: result[''status''] = Error elif status == HOTPLUG_STATUS_BUSY: - result[''status''] = Busy + return 1 else: result[''status''] = Connected else: return 1 We would time out if it it stays busy for DEVICE_CREATE_TIMEOUT. Not sure if we would need to do an unwatch in that case. Thanks, Chuck _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel