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HDFS-7263. Snapshot read can reveal future bytes for appended files. Contributed by Tao Luo.

This commit is contained in:
Tao Luo 2014-10-29 20:20:11 -07:00 committed by Konstantin V Shvachko
parent 51f621c01c
commit 8bfef59029
3 changed files with 37 additions and 11 deletions
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3
hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
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@ -114,6 +114,9 @@ Release 2.7.0 - UNRELEASED
HDFS-7235. DataNode#transferBlock should report blocks that don't exist
using reportBadBlock (yzhang via cmccabe)
HDFS-7263. Snapshot read can reveal future bytes for appended files.
(Tao Luo via shv)
Release 2.6.0 - UNRELEASED

3
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSInputStream.java
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@ -804,7 +804,8 @@ private int readWithStrategy(ReaderStrategy strategy, int off, int len) throws I
}
int realLen = (int) Math.min(len, (blockEnd - pos + 1L));
if (locatedBlocks.isLastBlockComplete()) {
realLen = (int) Math.min(realLen, locatedBlocks.getFileLength());
realLen = (int) Math.min(realLen,
locatedBlocks.getFileLength() - pos);
}
int result = readBuffer(strategy, off, realLen, corruptedBlockMap);

42
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/snapshot/TestSnapshotFileLength.java
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@ -21,7 +21,10 @@
import java.io.PrintStream;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.hdfs.AppendTestUtil;
import org.apache.hadoop.hdfs.DFSConfigKeys;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
@ -55,6 +58,8 @@ public class TestSnapshotFileLength {
@Before
public void setUp() throws Exception {
conf.setLong(DFSConfigKeys.DFS_NAMENODE_MIN_BLOCK_SIZE_KEY, BLOCKSIZE);
conf.setInt(DFSConfigKeys.DFS_BYTES_PER_CHECKSUM_KEY, BLOCKSIZE);
cluster = new MiniDFSCluster.Builder(conf).numDataNodes(REPLICATION)
.build();
cluster.waitActive();
@ -81,40 +86,57 @@ public void testSnapshotfileLength() throws Exception {
int bytesRead;
byte[] buffer = new byte[BLOCKSIZE * 8];
int origLen = BLOCKSIZE + 1;
int toAppend = BLOCKSIZE;
FSDataInputStream fis = null;
FileStatus fileStatus = null;
// Create and write a file.
Path file1 = new Path(sub, file1Name);
DFSTestUtil.createFile(hdfs, file1, 0, REPLICATION, SEED);
DFSTestUtil.appendFile(hdfs, file1, BLOCKSIZE);
DFSTestUtil.createFile(hdfs, file1, BLOCKSIZE, 0, BLOCKSIZE, REPLICATION, SEED);
DFSTestUtil.appendFile(hdfs, file1, origLen);
// Create a snapshot on the parent directory.
hdfs.allowSnapshot(sub);
hdfs.createSnapshot(sub, snapshot1);
// Write more data to the file.
DFSTestUtil.appendFile(hdfs, file1, BLOCKSIZE);
Path file1snap1
= SnapshotTestHelper.getSnapshotPath(sub, snapshot1, file1Name);
// Append to the file.
FSDataOutputStream out = hdfs.append(file1);
try {
AppendTestUtil.write(out, 0, toAppend);
// Test reading from snapshot of file that is open for append
byte[] dataFromSnapshot = DFSTestUtil.readFileBuffer(hdfs, file1snap1);
assertThat("Wrong data size in snapshot.",
dataFromSnapshot.length, is(origLen));
} finally {
out.close();
}
// Make sure we can read the entire file via its non-snapshot path.
fileStatus = hdfs.getFileStatus(file1);
assertThat(fileStatus.getLen(), is((long) BLOCKSIZE * 2));
assertThat(fileStatus.getLen(), is((long) origLen + toAppend));
fis = hdfs.open(file1);
bytesRead = fis.read(0, buffer, 0, buffer.length);
assertThat(bytesRead, is(BLOCKSIZE * 2));
assertThat(bytesRead, is(origLen + toAppend));
fis.close();
// Try to open the file via its snapshot path.
Path file1snap1 =
SnapshotTestHelper.getSnapshotPath(sub, snapshot1, file1Name);
fis = hdfs.open(file1snap1);
fileStatus = hdfs.getFileStatus(file1snap1);
assertThat(fileStatus.getLen(), is((long) BLOCKSIZE));
assertThat(fileStatus.getLen(), is((long) origLen));
// Make sure we can only read up to the snapshot length.
bytesRead = fis.read(0, buffer, 0, buffer.length);
assertThat(bytesRead, is(BLOCKSIZE));
assertThat(bytesRead, is(origLen));
fis.close();
byte[] dataFromSnapshot = DFSTestUtil.readFileBuffer(hdfs,
file1snap1);
assertThat("Wrong data size in snapshot.",
dataFromSnapshot.length, is(origLen));
}
/**