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July 2007

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77 discussions

[Libvir] PATCH: Fix remote driver to handle network API for local non-QEMU
by Daniel P. Berrange 04 Jul '07

04 Jul '07

The remote_internal.c code is basically a no-op in its remoteNetworkOpen method. This means the remote driver will only handle the networking APIs, if it is also handling the main domain APIs. This works fine if connecting to a remote URI, or if using QEMU URIs, but it does not work if using the test or Xen drivers. To make this work the remoteNetworkOpen method needs to open a connection to the remote daemon IIF the remoteOpen method did not already open one. So the attached patch adds the neccessary logic in remoteNetworkOpen. It also adds code to remoteNetworkClose to make it shutdown& free the connection IIF it was opened by the remoteNetworkOpen method. This is what the extra 'networkOnly' field in the 'struct private_data' is used to check. Second, all of the implementations of virNetwork* APIs in the remote_internal.c driver must use the 'struct private_data *' from networkPrivateData field in virConnectPtr, not the 'privateData' field. This is because the 'privateData' field is probably storing data related to the Xen or Test drivers. Third, this also fixes the qemu_driver.c which incorrectly used the privateData field insteadof the networkPrivateData field for 2 of the networking APIs, and finally makes sure the qemu_driver.c also acccepts the use of qemu:///session APIs for root user. Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|

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[Libvir] Proposal: libvirt should remove or rename a save file after a successful restore
by Richard W.M. Jones 02 Jul '07

02 Jul '07

Chris Lalancette found this problem: https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=246105 <quote> Once an "xm restore" has successfully completed, the -save file that it came from should really be deleted. Restoring a domain a second time from the same save file will result in disk corruption; the kernel VM state (in the saved file) will be in an inconsistent state with respect to what is actually on disk (in the domain disk file). The only valid use I can see for the -save file after a restore is possibly for some crash analysis, but even that could be worked around by renaming the save file after a success. In particular, I just ran into this situation (and I'm worried customers might do the same): [and then he goes on to describe a scenario in which you can commonly hit this situation] </quote> So the obvious and simple solution, it seems to me, is just to change libvirt.c:virDomainRestore so that if the driver underneath it returns from the restore without error, then we either remove or rename the restore file. It's a trivial patch -- what do people think? My thoughts: * Removing the file might seem quite abrupt/unexpected, and there is the possibility of data loss. * You have to rename the file as a hidden file (dotfile) in order for xendomains to ignore it. However these files are big and having large, hidden files which build up in number over time sounds like it could be a bad thing. * This might be considered a significant behaviour change. * It's easier to handle this for the remote case if we make the change inside libvirt, rather than in virsh etc. Rich. -- Emerging Technologies, Red Hat - http://et.redhat.com/~rjones/ Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 03798903

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