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HADOOP-18530. ChecksumFileSystem::readVectored might return byte buffers not positioned at 0 (#5168)

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Contributed by Harshit Gupta
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HarshitGupta11 2022-11-29 20:21:22 +05:30 committed by GitHub
parent 35c65005d0
commit 0ef572abed
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2 changed files with 13 additions and 0 deletions
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7
hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/VectoredReadUtils.java
View File

@ -307,9 +307,16 @@ public static ByteBuffer sliceTo(ByteBuffer readData, long readOffset,
FileRange request) {
int offsetChange = (int) (request.getOffset() - readOffset);
int requestLength = request.getLength();
// Create a new buffer that is backed by the original contents
// The buffer will have position 0 and the same limit as the original one
readData = readData.slice();
// Change the offset and the limit of the buffer as the reader wants to see
// only relevant data
readData.position(offsetChange);
readData.limit(offsetChange + requestLength);
// Create a new buffer after the limit change so that only that portion of the data is
// returned to the reader.
readData = readData.slice();
return readData;
}

6
hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/TestVectoredReadUtils.java
View File

@ -61,6 +61,9 @@ public void testSliceTo() {
.describedAs("Slicing on the same offset shouldn't " +
"create a new buffer")
.isEqualTo(slice);
Assertions.assertThat(slice.position())
.describedAs("Slicing should return buffers starting from position 0")
.isEqualTo(0);
// try slicing a range
final int offset = 100;
@ -77,6 +80,9 @@ public void testSliceTo() {
.describedAs("Slicing should use the same underlying " +
"data")
.isEqualTo(slice.array());
Assertions.assertThat(slice.position())
.describedAs("Slicing should return buffers starting from position 0")
.isEqualTo(0);
// test the contents of the slice
intBuffer = slice.asIntBuffer();
for(int i=0; i < sliceLength / Integer.BYTES; ++i) {