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HDFS-9133. ExternalBlockReader and ReplicaAccessor need to return -1 on read when at EOF. (Colin Patrick McCabe via Lei (Eddy) Xu) 

(cherry picked from commit 67b0e967f0)
This commit is contained in:
Lei Xu 2015-09-25 16:01:41 -07:00
parent 1a2870f6ff
commit 82d4c05b2d
4 changed files with 30 additions and 8 deletions
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6
hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/ExternalBlockReader.java
View File

@ -45,6 +45,9 @@ public final class ExternalBlockReader implements BlockReader {
@Override
public int read(byte[] buf, int off, int len) throws IOException {
int nread = accessor.read(pos, buf, off, len);
if (nread < 0) {
return nread;
}
pos += nread;
return nread;
}
@ -52,6 +55,9 @@ public int read(byte[] buf, int off, int len) throws IOException {
@Override
public int read(ByteBuffer buf) throws IOException {
int nread = accessor.read(pos, buf);
if (nread < 0) {
return nread;
}
pos += nread;
return nread;
}

10
hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/ReplicaAccessor.java
View File

@ -40,8 +40,9 @@ public abstract class ReplicaAccessor {
*
* @return The number of bytes read. If the read extends past the end
* of the replica, a short read count will be returned. We
* will never return a negative number. We will never
* return a short read count unless EOF is reached.
* will should return -1 if EOF is reached and no bytes
* can be returned. We will never return a short read
* count unless EOF is reached.
*/
public abstract int read(long pos, byte[] buf, int off, int len)
throws IOException;
@ -58,8 +59,9 @@ public abstract int read(long pos, byte[] buf, int off, int len)
*
* @return The number of bytes read. If the read extends past the end
* of the replica, a short read count will be returned. We
* will never return a negative number. We will never return
* a short read count unless EOF is reached.
* should return -1 if EOF is reached and no bytes can be
* returned. We will never return a short read count unless
* EOF is reached.
*/
public abstract int read(long pos, ByteBuffer buf) throws IOException;

3
hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
View File

@ -623,6 +623,9 @@ Release 2.8.0 - UNRELEASED
HDFS-9132. Pass genstamp to ReplicaAccessorBuilder. (Colin Patrick McCabe via
Lei (Eddy) Xu)
HDFS-9133. ExternalBlockReader and ReplicaAccessor need to return -1 on read
when at EOF. (Colin Patrick McCabe via Lei (Eddy) Xu)
OPTIMIZATIONS
HDFS-8026. Trace FSOutputSummer#writeChecksumChunks rather than

19
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestExternalBlockReader.java
View File

@ -190,8 +190,8 @@ public synchronized int read(long pos, byte[] buf, int off, int len)
"than 0 at " + pos);
return 0;
}
int i = 0, nread = 0;
for (int ipos = (int)pos;
int i = 0, nread = 0, ipos;
for (ipos = (int)pos;
(ipos < contents.length) && (nread < len);
ipos++) {
buf[i++] = contents[ipos];
@ -199,6 +199,9 @@ public synchronized int read(long pos, byte[] buf, int off, int len)
totalRead++;
LOG.info("ipos = " + ipos + ", contents.length = " + contents.length + ", nread = " + nread + ", len = " + len);
}
if ((nread == 0) && (ipos >= contents.length)) {
return -1;
}
return nread;
}
@ -211,8 +214,8 @@ public synchronized int read(long pos, ByteBuffer buf) throws IOException {
"than 0 at " + pos);
return 0;
}
int i = 0, nread = 0;
for (int ipos = (int)pos;
int i = 0, nread = 0, ipos;
for (ipos = (int)pos;
ipos < contents.length; ipos++) {
try {
buf.put(contents[ipos]);
@ -222,6 +225,9 @@ public synchronized int read(long pos, ByteBuffer buf) throws IOException {
nread++;
totalRead++;
}
if ((nread == 0) && (ipos >= contents.length)) {
return -1;
}
return nread;
}
@ -304,6 +310,11 @@ public void testExternalBlockReader() throws Exception {
Assert.assertEquals(1024L, accessor.totalRead);
Assert.assertEquals("", accessor.getError());
Assert.assertEquals(1, accessor.numCloses);
byte[] tempBuf = new byte[5];
Assert.assertEquals(-1, accessor.read(TEST_LENGTH,
tempBuf, 0, 0));
Assert.assertEquals(-1, accessor.read(TEST_LENGTH,
tempBuf, 0, tempBuf.length));
accessors.remove(uuid);
} finally {
dfs.close();