/// <summary>Verifies the block's checksum.</summary>
/// <remarks>Verifies the block's checksum. This is an I/O intensive operation.</remarks>
/// <exception cref="System.IO.IOException"/>
/// <exception cref="Org.Apache.Hadoop.FS.ChecksumException"/>
private static void VerifyChecksum(long length, FileInputStream metaIn, FileChannel
blockChannel, string blockFileName)
{
// Verify the checksum from the block's meta file
// Get the DataChecksum from the meta file header
BlockMetadataHeader header = BlockMetadataHeader.ReadHeader(new DataInputStream(new
BufferedInputStream(metaIn, BlockMetadataHeader.GetHeaderSize())));
FileChannel metaChannel = null;
try
{
metaChannel = metaIn.GetChannel();
if (metaChannel == null)
{
throw new IOException("Block InputStream meta file has no FileChannel.");
}
DataChecksum checksum = header.GetChecksum();
int bytesPerChecksum = checksum.GetBytesPerChecksum();
int checksumSize = checksum.GetChecksumSize();
int numChunks = (8 * 1024 * 1024) / bytesPerChecksum;
ByteBuffer blockBuf = ByteBuffer.Allocate(numChunks * bytesPerChecksum);
ByteBuffer checksumBuf = ByteBuffer.Allocate(numChunks * checksumSize);
// Verify the checksum
int bytesVerified = 0;
while (bytesVerified < length)
{
Preconditions.CheckState(bytesVerified % bytesPerChecksum == 0, "Unexpected partial chunk before EOF"
);
System.Diagnostics.Debug.Assert(bytesVerified % bytesPerChecksum == 0);
int bytesRead = FillBuffer(blockChannel, blockBuf);
if (bytesRead == -1)
{
throw new IOException("checksum verification failed: premature EOF");
}
blockBuf.Flip();
// Number of read chunks, including partial chunk at end
int chunks = (bytesRead + bytesPerChecksum - 1) / bytesPerChecksum;
checksumBuf.Limit(chunks * checksumSize);
FillBuffer(metaChannel, checksumBuf);
checksumBuf.Flip();
checksum.VerifyChunkedSums(blockBuf, checksumBuf, blockFileName, bytesVerified);
// Success
bytesVerified += bytesRead;
blockBuf.Clear();
checksumBuf.Clear();
}
}
finally
{
IOUtils.CloseQuietly(metaChannel);
}
}
/// <exception cref="System.IO.IOException"/>
internal override int Run(IList <string> args)
{
if (args.Count == 0)
{
System.Console.Out.WriteLine(this.usageText);
System.Console.Out.WriteLine(this.helpText + "\n");
return(1);
}
string blockFile = StringUtils.PopOptionWithArgument("-block", args);
string metaFile = StringUtils.PopOptionWithArgument("-meta", args);
if (metaFile == null)
{
System.Console.Error.WriteLine("You must specify a meta file with -meta");
return(1);
}
FileInputStream metaStream = null;
FileInputStream dataStream = null;
FileChannel metaChannel = null;
FileChannel dataChannel = null;
DataInputStream checksumStream = null;
try
{
BlockMetadataHeader header;
try
{
metaStream = new FileInputStream(metaFile);
checksumStream = new DataInputStream(metaStream);
header = BlockMetadataHeader.ReadHeader(checksumStream);
metaChannel = metaStream.GetChannel();
metaChannel.Position(DebugAdmin.HeaderLen);
}
catch (RuntimeException e)
{
System.Console.Error.WriteLine("Failed to read HDFS metadata file header for " +
metaFile + ": " + StringUtils.StringifyException(e));
return(1);
}
catch (IOException e)
{
System.Console.Error.WriteLine("Failed to read HDFS metadata file header for " +
metaFile + ": " + StringUtils.StringifyException(e));
return(1);
}
DataChecksum checksum = header.GetChecksum();
System.Console.Out.WriteLine("Checksum type: " + checksum.ToString());
if (blockFile == null)
{
return(0);
}
ByteBuffer metaBuf;
ByteBuffer dataBuf;
try
{
dataStream = new FileInputStream(blockFile);
dataChannel = dataStream.GetChannel();
int ChecksumsPerBuf = 1024 * 32;
metaBuf = ByteBuffer.Allocate(checksum.GetChecksumSize() * ChecksumsPerBuf);
dataBuf = ByteBuffer.Allocate(checksum.GetBytesPerChecksum() * ChecksumsPerBuf);
}
catch (IOException e)
{
System.Console.Error.WriteLine("Failed to open HDFS block file for " + blockFile
+ ": " + StringUtils.StringifyException(e));
return(1);
}
long offset = 0;
while (true)
{
dataBuf.Clear();
int dataRead = -1;
try
{
dataRead = dataChannel.Read(dataBuf);
if (dataRead < 0)
{
break;
}
}
catch (IOException e)
{
System.Console.Error.WriteLine("Got I/O error reading block file " + blockFile +
"from disk at offset " + dataChannel.Position() + ": " + StringUtils.StringifyException
(e));
return(1);
}
try
{
int csumToRead = (((checksum.GetBytesPerChecksum() - 1) + dataRead) / checksum.GetBytesPerChecksum
()) * checksum.GetChecksumSize();
metaBuf.Clear();
metaBuf.Limit(csumToRead);
metaChannel.Read(metaBuf);
dataBuf.Flip();
metaBuf.Flip();
}
catch (IOException e)
{
System.Console.Error.WriteLine("Got I/O error reading metadata file " + metaFile
+ "from disk at offset " + metaChannel.Position() + ": " + StringUtils.StringifyException
(e));
return(1);
}
try
{
checksum.VerifyChunkedSums(dataBuf, metaBuf, blockFile, offset);
}
catch (IOException e)
{
System.Console.Out.WriteLine("verifyChunkedSums error: " + StringUtils.StringifyException
(e));
return(1);
}
offset += dataRead;
}
System.Console.Out.WriteLine("Checksum verification succeeded on block file " + blockFile
);
return(0);
}
finally
{
IOUtils.Cleanup(null, metaStream, dataStream, checksumStream);
}
}