Created attachment 936153 [details]
vdsm+engine logs

Description of problem:
The Active VM snapshot is removable if executed from rest-api and the vm has no disks.
when adding a disk to the VM after removing the Active snapshot and attempting to take a snapshot operation fails with:

2014-09-10 11:05:04,529 ERROR [org.ovirt.engine.core.bll.CreateAllSnapshotsFromVmCommand] (org.ovirt.thread.pool-6-thread-21) Command org.ovirt.engine.core.bll.CreateAllSnapshotsFromVmCommand throw exception: org.springframework.dao.DataIntegrityViolationException: CallableStatementCallback; SQL [{call insertsnapshot(?, ?, ?, ?, ?, ?, ?, ?, ?)}]; ERROR: null value in column "snapshot_id" violates not-null constraint
  Where: SQL statement "INSERT INTO snapshots( snapshot_id, status, vm_id, snapshot_type, description, creation_date, app_list, vm_configuration, memory_volume) VALUES(  $1 ,  $2 ,  $3 ,  $4 ,  $5 ,  $6 ,  $7 ,  $8 ,  $9 )"
PL/pgSQL function "insertsnapshot" line 2 at SQL statement; nested exception is org.postgresql.util.PSQLException: ERROR: null value in column "snapshot_id" violates not-null constraint
  Where: SQL statement "INSERT INTO snapshots( snapshot_id, status, vm_id, snapshot_type, description, creation_date, app_list, vm_configuration, memory_volume) VALUES(  $1 ,  $2 ,  $3 ,  $4 ,  $5 ,  $6 ,  $7 ,  $8 ,  $9 )"
PL/pgSQL function "insertsnapshot" line 2 at SQL statement
        at org.springframework.jdbc.support.SQLErrorCodeSQLExceptionTranslator.doTranslate(SQLErrorCodeSQLExceptionTranslator.java:245) [spring-jdbc.jar:3.1.1.RELEASE]
        at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:72) [spring-jdbc.jar:3.1.1.RELEASE]
        at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:1030) [spring-jdbc.jar:3.1.1.RELEASE]
        at org.springframework.jdbc.core.JdbcTemplate.call(JdbcTemplate.java:1064) [spring-jdbc.jar:3.1.1.RELEASE]
        at org.springframework.jdbc.core.simple.AbstractJdbcCall.executeCallInternal(AbstractJdbcCall.java:388) [spring-jdbc.jar:3.1.1.RELEASE]
        at org.springframework.jdbc.core.simple.AbstractJdbcCall.doExecute(AbstractJdbcCall.java:351) [spring-jdbc.jar:3.1.1.RELEASE]
        at org.springframework.jdbc.core.simple.SimpleJdbcCall.execute(SimpleJdbcCall.java:181) [spring-jdbc.jar:3.1.1.RELEASE]
        at org.ovirt.engine.core.dal.dbbroker.SimpleJdbcCallsHandler.executeImpl(SimpleJdbcCallsHandler.java:141) [dal.jar:]
        at org.ovirt.engine.core.dal.dbbroker.SimpleJdbcCallsHandler.executeImpl(SimpleJdbcCallsHandler.java:136) [dal.jar:]
        at org.ovirt.engine.core.dal.dbbroker.SimpleJdbcCallsHandler.executeModification(SimpleJdbcCallsHandler.java:74) [dal.jar:]
        at org.ovirt.engine.core.dao.DefaultGenericDaoDbFacade.save(DefaultGenericDaoDbFacade.java:93) [dal.jar:]
        at org.ovirt.engine.core.bll.snapshots.SnapshotsManager.addSnapshot(SnapshotsManager.java:348) [bll.jar:]
        at org.ovirt.engine.core.bll.snapshots.SnapshotsManager.addSnapshot(SnapshotsManager.java:316) [bll.jar:]
        at org.ovirt.engine.core.bll.CreateAllSnapshotsFromVmCommand.addSnapshotToDB(CreateAllSnapshotsFromVmCommand.java:235) [bll.jar:]
        at org.ovirt.engine.core.bll.CreateAllSnapshotsFromVmCommand.executeVmCommand(CreateAllSnapshotsFromVmCommand.java:194) [bll.jar:]
        at org.ovirt.engine.core.bll.VmCommand.executeCommand(VmCommand.java:100) [bll.jar:]
        at org.ovirt.engine.core.bll.CommandBase.executeWithoutTransaction(CommandBase.java:1167) [bll.jar:]
        at org.ovirt.engine.core.bll.CommandBase.executeActionInTransactionScope(CommandBase.java:1298) [bll.jar:]
        at org.ovirt.engine.core.bll.CommandBase.runInTransaction(CommandBase.java:1920) [bll.jar:]
        at org.ovirt.engine.core.utils.transaction.TransactionSupport.executeInSuppressed(TransactionSupport.java:174) [utils.jar:]
        at org.ovirt.engine.core.utils.transaction.TransactionSupport.executeInScope(TransactionSupport.java:116) [utils.jar:]
        at org.ovirt.engine.core.bll.CommandBase.execute(CommandBase.java:1319) [bll.jar:]
        at org.ovirt.engine.core.bll.CommandBase.executeAction(CommandBase.java:344) [bll.jar:]
        at org.ovirt.engine.core.bll.MultipleActionsRunner.executeValidatedCommand(MultipleActionsRunner.java:191) [bll.jar:]
        at org.ovirt.engine.core.bll.MultipleActionsRunner.runCommands(MultipleActionsRunner.java:158) [bll.jar:]
        at org.ovirt.engine.core.bll.MultipleActionsRunner$2.run(MultipleActionsRunner.java:167) [bll.jar:]
        at org.ovirt.engine.core.utils.threadpool.ThreadPoolUtil$InternalWrapperRunnable.run(ThreadPoolUtil.java:90) [utils.jar:]
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) [rt.jar:1.7.0_65]
        at java.util.concurrent.FutureTask.run(FutureTask.java:262) [rt.jar:1.7.0_65]
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [rt.jar:1.7.0_65]
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [rt.jar:1.7.0_65]
        at java.lang.Thread.run(Thread.java:745) [rt.jar:1.7.0_65]
Caused by: org.postgresql.util.PSQLException: ERROR: null value in column "snapshot_id" violates not-null constraint
  Where: SQL statement "INSERT INTO snapshots( snapshot_id, status, vm_id, snapshot_type, description, creation_date, app_list, vm_configuration, memory_volume) VALUES(  $1 ,  $2 ,  $3 ,  $4 ,  $5 ,  $6 ,  $7 ,  $8 ,  $9 )"
PL/pgSQL function "insertsnapshot" line 2 at SQL statement
        at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2101)
        at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1834)
        at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:255)
        at org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:510)
        at org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:386)
        at org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:379)
        at org.jboss.jca.adapters.jdbc.CachedPreparedStatement.execute(CachedPreparedStatement.java:297)
        at org.jboss.jca.adapters.jdbc.WrappedPreparedStatement.execute(WrappedPreparedStatement.java:404)
        at org.springframework.jdbc.core.JdbcTemplate$6.doInCallableStatement(JdbcTemplate.java:1066) [spring-jdbc.jar:3.1.1.RELEASE]
        at org.springframework.jdbc.core.JdbcTemplate$6.doInCallableStatement(JdbcTemplate.java:1) [spring-jdbc.jar:3.1.1.RELEASE]
        at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:1014) [spring-jdbc.jar:3.1.1.RELEASE]
        ... 29 more

plus there's nothing to do with this VM since it cannot be activated

Version-Release number of selected component (if applicable):
rhev vt2.2

How reproducible:
100%

Steps to Reproduce:
1.create a VM(do not add any disks)
2.delete it's snapshot
3.add disk to the VM
4.try to take a snapshot

Actual results:
db exceptions,useless VM

Expected results:
Operation of removing the Active VM's snapshot should be banned

Additional info: