[
https://issues.apache.org/jira/browse/HDFS-15759?focusedWorklogId=567400&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-567400
]
ASF GitHub Bot logged work on HDFS-15759:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 17/Mar/21 02:46
Start Date: 17/Mar/21 02:46
Worklog Time Spent: 10m
Work Description: aajisaka commented on a change in pull request #2585:
URL: https://github.com/apache/hadoop/pull/2585#discussion_r595673715
##########
File path:
hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/erasurecode/rawcoder/DecodingValidator.java
##########
@@ -0,0 +1,189 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.io.erasurecode.rawcoder;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+import
org.apache.hadoop.thirdparty.com.google.common.annotations.VisibleForTesting;
+import org.apache.hadoop.io.erasurecode.ECChunk;
+
+import java.io.IOException;
+import java.nio.ByteBuffer;
+
+/**
+ * A utility class to validate decoding.
+ */
+@InterfaceAudience.Private
+public class DecodingValidator {
+
+ private final RawErasureDecoder decoder;
+ private ByteBuffer buffer;
+ private int[] newValidIndexes;
+ private int newErasedIndex;
+
+ public DecodingValidator(RawErasureDecoder decoder) {
+ this.decoder = decoder;
+ }
+
+ /**
+ * Validate outputs decoded from inputs, by decoding an input back from
+ * the outputs and comparing it with the original one.
+ *
+ * For instance, in RS (6, 3), let (d0, d1, d2, d3, d4, d5) be sources
+ * and (p0, p1, p2) be parities, and assume
+ * inputs = [d0, null (d1), d2, d3, d4, d5, null (p0), p1, null (p2)];
+ * erasedIndexes = [1, 6];
+ * outputs = [d1, p1].
+ * Then
+ * 1. Create new inputs, erasedIndexes and outputs for validation so that
+ * the inputs could contain the decoded outputs, and decode them:
+ * newInputs = [d1, d2, d3, d4, d5, p1]
+ * newErasedIndexes = [0]
+ * newOutputs = [d0']
+ * 2. Compare d0 and d0'. The comparison will fail with high probability
+ * when the initial outputs are wrong.
+ *
+ * Note that the input buffers' positions must be the ones where data are
+ * read: If the input buffers have been processed by a decoder, the buffers'
+ * positions must be reset before being passed into this method.
+ *
+ * This method does not change outputs and erasedIndexes.
+ *
+ * @param inputs input buffers used for decoding. The buffers' position
+ * are moved to the end after this method.
+ * @param erasedIndexes indexes of erased units used for decoding
+ * @param outputs decoded output buffers, which are ready to be read after
+ * the call
+ * @throws IOException
+ */
+ public void validate(ByteBuffer[] inputs, int[] erasedIndexes,
+ ByteBuffer[] outputs) throws IOException {
+ markBuffers(outputs);
+
+ try {
+ ByteBuffer validInput = CoderUtil.findFirstValidInput(inputs);
+ boolean isDirect = validInput.isDirect();
+ int capacity = validInput.capacity();
+ int remaining = validInput.remaining();
+
+ // Init buffer
+ if (buffer == null) {
+ buffer = allocateBuffer(isDirect, capacity);
+ } else if (buffer.isDirect() != isDirect
+ || buffer.capacity() < remaining) {
+ buffer = allocateBuffer(isDirect, capacity);
+ }
Review comment:
```suggestion
// Init buffer
if (buffer == null || buffer.isDirect() != isDirect ||
buffer.capacity() < remaining) {
buffer = allocateBuffer(isDirect, capacity);
}
```
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org
Issue Time Tracking
-------------------
Worklog Id: (was: 567400)
Time Spent: 4h 50m (was: 4h 40m)
> EC: Verify EC reconstruction correctness on DataNode
> ----------------------------------------------------
>
> Key: HDFS-15759
> URL: https://issues.apache.org/jira/browse/HDFS-15759
> Project: Hadoop HDFS
> Issue Type: New Feature
> Components: datanode, ec, erasure-coding
> Affects Versions: 3.4.0
> Reporter: Toshihiko Uchida
> Assignee: Toshihiko Uchida
> Priority: Major
> Labels: pull-request-available
> Time Spent: 4h 50m
> Remaining Estimate: 0h
>
> EC reconstruction on DataNode has caused data corruption: HDFS-14768,
> HDFS-15186 and HDFS-15240. Those issues occur under specific conditions and
> the corruption is neither detected nor auto-healed by HDFS. It is obviously
> hard for users to monitor data integrity by themselves, and even if they find
> corrupted data, it is difficult or sometimes impossible to recover them.
> To prevent further data corruption issues, this feature proposes a simple and
> effective way to verify EC reconstruction correctness on DataNode at each
> reconstruction process.
> It verifies correctness of outputs decoded from inputs as follows:
> 1. Decoding an input with the outputs;
> 2. Compare the decoded input with the original input.
> For instance, in RS-6-3, assume that outputs [d1, p1] are decoded from inputs
> [d0, d2, d3, d4, d5, p0]. Then the verification is done by decoding d0 from
> [d1, d2, d3, d4, d5, p1], and comparing the original and decoded data of d0.
> When an EC reconstruction task goes wrong, the comparison will fail with high
> probability.
> Then the task will also fail and be retried by NameNode.
> The next reconstruction will succeed if the condition triggered the failure
> is gone.
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
---------------------------------------------------------------------
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
