Divide by zero exception if running with a small block size

[zrlio]

Divide by zero exception if running with a small block size

[animeshtrivedi]

I cannot reproduce the same error when running for < 1MB block sizes (with 1MB client buffer size). But when ran out of block (or with a faulty, zero block storage node), It still is an issue. Updated stack dump:

17/04/20 13:34:19 INFO netty: A new connection has arrived from : /127.0.0.1:59490
17/04/20 13:34:19 INFO netty: ERROR: Unknown error/ by zero
java.lang.ArithmeticException: / by zero
	at com.ibm.crail.namenode.StorageTier$RoundRobinBlockSelection.getNext(BlockStore.java:187)
	at com.ibm.crail.namenode.StorageTier$DataNodeArray.get(BlockStore.java:227)
	at com.ibm.crail.namenode.StorageTier$DataNodeArray.access$000(BlockStore.java:202)
	at com.ibm.crail.namenode.StorageTier.getBlock(BlockStore.java:120)
	at com.ibm.crail.namenode.BlockStore.getBlock(BlockStore.java:65)
	at com.ibm.crail.namenode.NameNodeService.createFile(NameNodeService.java:100)
	at com.ibm.crail.namenode.rpc.netty.NamenodeProcessor.channelRead0(NamenodeProcessor.java:52)
	at com.ibm.crail.namenode.rpc.netty.NamenodeProcessor.channelRead0(NamenodeProcessor.java:36)
	at io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:105)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:308)
	at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:294)
	at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:244)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:308)
	at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:294)
	at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:846)
	at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:131)
	at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:511)
	at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:468)
	at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:382)
	at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:354)
	at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:111)
	at io.netty.util.concurrent.DefaultThreadFactory$DefaultRunnableDecorator.run(DefaultThreadFactory.java:137)
	at java.lang.Thread.run(Thread.java:745)

[patrickstuedi]

Fixed in 487780a or earler.