/// <summary>Scan a block.</summary>
/// <param name="cblock">The block to scan.</param>
/// <param name="bytesPerSec">The bytes per second to scan at.</param>
/// <returns>
/// The length of the block that was scanned, or
/// -1 if the block could not be scanned.
/// </returns>
private long ScanBlock(ExtendedBlock cblock, long bytesPerSec)
{
// 'cblock' has a valid blockId and block pool id, but we don't yet know the
// genstamp the block is supposed to have. Ask the FsDatasetImpl for this
// information.
ExtendedBlock block = null;
try
{
Block b = volume.GetDataset().GetStoredBlock(cblock.GetBlockPoolId(), cblock.GetBlockId
());
if (b == null)
{
Log.Info("FileNotFound while finding block {} on volume {}", cblock, volume.GetBasePath
());
}
else
{
block = new ExtendedBlock(cblock.GetBlockPoolId(), b);
}
}
catch (FileNotFoundException)
{
Log.Info("FileNotFoundException while finding block {} on volume {}", cblock, volume
.GetBasePath());
}
catch (IOException)
{
Log.Warn("I/O error while finding block {} on volume {}", cblock, volume.GetBasePath
());
}
if (block == null)
{
return(-1);
}
// block not found.
BlockSender blockSender = null;
try
{
blockSender = new BlockSender(block, 0, -1, false, true, true, datanode, null, CachingStrategy
.NewDropBehind());
throttler.SetBandwidth(bytesPerSec);
long bytesRead = blockSender.SendBlock(nullStream, null, throttler);
resultHandler.Handle(block, null);
return(bytesRead);
}
catch (IOException e)
{
resultHandler.Handle(block, e);
}
finally
{
IOUtils.Cleanup(null, blockSender);
}
return(-1);
}
