Description of problem:

Activating a FC LUN while the guest is running results in an IndexOutOfBoundsException exception being thrown as FC Luns have no rows within the storage_server_connections table. BZ#854141 shows another example failure when starting guests, this was resolved by http://gerrit.ovirt.org/#/c/7764/. Really we need the same checks in the following method.

ovirt-engine/backend/manager/modules/bll/src/main/java/org/ovirt/engine/core/bll/AbstractDiskVmCommand.java

~~~
 49     protected void performPlugCommnad(VDSCommandType commandType,
 50             Disk disk, VmDevice vmDevice) {
 51         if (disk.getDiskStorageType() == DiskStorageType.LUN) {
 52             LunDisk lunDisk = (LunDisk) disk;
 53             if (commandType == VDSCommandType.HotPlugDisk) {
 54                 LUNs lun = lunDisk.getLun();
 55                 lun.setLunConnections(new ArrayList<storage_server_connections>(getDbFacade()
 56                         .getStorageServerConnectionDAO()
 57                         .getAllForLun(lun.getLUN_id())));
 58                 if (!StorageHelperDirector.getInstance()
 59                         .getItem(lun.getLunConnections().get(0).getstorage_type())
 60                         .ConnectStorageToLunByVdsId(null,
 61                                 getVm().getrun_on_vds().getValue(),
 62                                 lun,
 63                                 getVm().getstorage_pool_id())) {
 64                     throw new VdcBLLException(VdcBllErrors.StorageServerConnectionError);
 65                 }
 66             }
 67         }
 68         runVdsCommand(commandType, new HotPlugDiskVDSParameters(getVm().getrun_on_vds().getValue(),
 69                 getVm().getId(), disk, vmDevice));
 70     }
~~~

~~~
12171 2013-02-11 14:25:18,116 ERROR [org.ovirt.engine.core.bll.HotPlugDiskToVmCommand] (pool-3-thread-50) [5ee28eb1] Command org.ovirt.engine.core.bll.HotPlugDiskToVmCommand throw exception: java.lang.IndexOutOfBoundsException: Index: 0,       Size: 0
12172     at java.util.ArrayList.rangeCheck(ArrayList.java:604) [rt.jar:1.7.0_09-icedtea]
12173     at java.util.ArrayList.get(ArrayList.java:382) [rt.jar:1.7.0_09-icedtea]
12174     at org.ovirt.engine.core.bll.AbstractDiskVmCommand.performPlugCommnad(AbstractDiskVmCommand.java:58) [engine-bll.jar:]
12175     at org.ovirt.engine.core.bll.HotPlugDiskToVmCommand.ExecuteVmCommand(HotPlugDiskToVmCommand.java:77) [engine-bll.jar:]
12176     at org.ovirt.engine.core.bll.VmCommand.executeCommand(VmCommand.java:78) [engine-bll.jar:]
12177     at org.ovirt.engine.core.bll.CommandBase.executeWithoutTransaction(CommandBase.java:876) [engine-bll.jar:]
12178     at org.ovirt.engine.core.bll.CommandBase.executeActionInTransactionScope(CommandBase.java:973) [engine-bll.jar:]
12179     at org.ovirt.engine.core.bll.CommandBase.runInTransaction(CommandBase.java:1372) [engine-bll.jar:]
12180     at org.ovirt.engine.core.utils.transaction.TransactionSupport.executeInSuppressed(TransactionSupport.java:168) [engine-utils.jar:]
12181     at org.ovirt.engine.core.utils.transaction.TransactionSupport.executeInScope(TransactionSupport.java:107) [engine-utils.jar:]
12182     at org.ovirt.engine.core.bll.CommandBase.execute(CommandBase.java:991) [engine-bll.jar:]
12183     at org.ovirt.engine.core.bll.CommandBase.executeAction(CommandBase.java:291) [engine-bll.jar:]
12184     at org.ovirt.engine.core.bll.MultipleActionsRunner.executeValidatedCommands(MultipleActionsRunner.java:182) [engine-bll.jar:]
12185     at org.ovirt.engine.core.bll.MultipleActionsRunner.RunCommands(MultipleActionsRunner.java:162) [engine-bll.jar:]
12186     at org.ovirt.engine.core.bll.MultipleActionsRunner$1.run(MultipleActionsRunner.java:84) [engine-bll.jar:]
12187     at org.ovirt.engine.core.utils.threadpool.ThreadPoolUtil$InternalWrapperRunnable.run(ThreadPoolUtil.java:64) [engine-utils.jar:]
12188     at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) [rt.jar:1.7.0_09-icedtea]
12189     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334) [rt.jar:1.7.0_09-icedtea]
12190     at java.util.concurrent.FutureTask.run(FutureTask.java:166) [rt.jar:1.7.0_09-icedtea]
12191     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110) [rt.jar:1.7.0_09-icedtea]
12192     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603) [rt.jar:1.7.0_09-icedtea]
12193     at java.lang.Thread.run(Thread.java:722) [rt.jar:1.7.0_09-icedtea]
[..]
12223 2013-02-11 14:25:30,403 ERROR [org.ovirt.engine.core.bll.HotPlugDiskToVmCommand] (pool-3-thread-50) [2ddff44c] Command org.ovirt.engine.core.bll.HotPlugDiskToVmCommand throw exception: java.lang.IndexOutOfBoundsException: Index: 0,       Size: 0
12224     at java.util.ArrayList.rangeCheck(ArrayList.java:604) [rt.jar:1.7.0_09-icedtea]
12225     at java.util.ArrayList.get(ArrayList.java:382) [rt.jar:1.7.0_09-icedtea]
12226     at org.ovirt.engine.core.bll.AbstractDiskVmCommand.performPlugCommnad(AbstractDiskVmCommand.java:58) [engine-bll.jar:]
12227     at org.ovirt.engine.core.bll.HotPlugDiskToVmCommand.ExecuteVmCommand(HotPlugDiskToVmCommand.java:77) [engine-bll.jar:]
12228     at org.ovirt.engine.core.bll.VmCommand.executeCommand(VmCommand.java:78) [engine-bll.jar:]
12229     at org.ovirt.engine.core.bll.CommandBase.executeWithoutTransaction(CommandBase.java:876) [engine-bll.jar:]
12230     at org.ovirt.engine.core.bll.CommandBase.executeActionInTransactionScope(CommandBase.java:973) [engine-bll.jar:]
12231     at org.ovirt.engine.core.bll.CommandBase.runInTransaction(CommandBase.java:1372) [engine-bll.jar:]
12232     at org.ovirt.engine.core.utils.transaction.TransactionSupport.executeInSuppressed(TransactionSupport.java:168) [engine-utils.jar:]
12233     at org.ovirt.engine.core.utils.transaction.TransactionSupport.executeInScope(TransactionSupport.java:107) [engine-utils.jar:]
12234     at org.ovirt.engine.core.bll.CommandBase.execute(CommandBase.java:991) [engine-bll.jar:]
12235     at org.ovirt.engine.core.bll.CommandBase.executeAction(CommandBase.java:291) [engine-bll.jar:]
12236     at org.ovirt.engine.core.bll.MultipleActionsRunner.executeValidatedCommands(MultipleActionsRunner.java:182) [engine-bll.jar:]
12237     at org.ovirt.engine.core.bll.MultipleActionsRunner.RunCommands(MultipleActionsRunner.java:162) [engine-bll.jar:]
12238     at org.ovirt.engine.core.bll.MultipleActionsRunner$1.run(MultipleActionsRunner.java:84) [engine-bll.jar:]
12239     at org.ovirt.engine.core.utils.threadpool.ThreadPoolUtil$InternalWrapperRunnable.run(ThreadPoolUtil.java:64) [engine-utils.jar:]
12240     at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) [rt.jar:1.7.0_09-icedtea]
12241     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334) [rt.jar:1.7.0_09-icedtea]
12242     at java.util.concurrent.FutureTask.run(FutureTask.java:166) [rt.jar:1.7.0_09-icedtea]
12243     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110) [rt.jar:1.7.0_09-icedtea]
12244     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603) [rt.jar:1.7.0_09-icedtea]
12245     at java.lang.Thread.run(Thread.java:722) [rt.jar:1.7.0_09-icedtea]
~~~

Version-Release number of selected component (if applicable):
rhevm-3.1.0-40

How reproducible:
I don't have FC LUNs to hand to confirm this but...

Activate FC Luns attached to a running guest.

Steps to Reproduce:
1. Attach a FC LUN to a given guest.
2. Activate the FC LUN.
3. Operation fails.
  
Actual results:
LUN fails to activate.

Expected results:
LUN activates.

Additional info:
The example logs will also show BZ#876109, an audit logging exception.