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https://issues.apache.org/jira/browse/HDFS-17965?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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ASF GitHub Bot updated HDFS-17965:
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Labels: pull-request-available (was: )
> DFSInputStream.close() leaks the block reader socket when the DFSClient is
> already closed
> -----------------------------------------------------------------------------------------
>
> Key: HDFS-17965
> URL: https://issues.apache.org/jira/browse/HDFS-17965
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: hdfs-client
> Environment: DFSInputStream.close() calls dfsClient.checkOpen() before
> closeCurrentBlockReaders():
> {code:java}
> public synchronized void close() throws IOException {
> try {
> if (!closed.compareAndSet(false, true)) { ... return; }
> dfsClient.checkOpen(); // throws if the client is closed
> ...
> closeCurrentBlockReaders(); // never reached in that case
> super.close();
> {code}
> If the DFSClient has already been closed (for example via
> FileSystem.closeAllForUGI() during shutdown/cleanup), checkOpen() throws
> "Filesystem closed" and the current block reader is never closed. Because
> the closed flag has already been CAS-ed(Compare-And-Set) to true, any further
> close() call
> is a no-op, so the block reader's socket to the DataNode can never be
> released for the lifetime of the client JVM.
> Production impact we observed: with DefaultContainerExecutor, the YARN
> NodeManager runs ContainerLocalizer inside the NM JVM. When a container is
> killed while localizing (YARN-11856), runLocalization()'s finally block
> closes the UGI filesystems while the download thread still holds an open
> DFSInputStream. The subsequent stream close() aborts at checkOpen() and
> leaks the socket inside the long-lived NM process. On the DataNode side the
> connection is stuck in FIN_WAIT1 with a send queue that never drains; on a
> ~600-node cluster this accumulated continuously until DataNodes carried
> large numbers of FIN_WAIT1 connections and NodeManagers leaked fds.
> Fix: release the block reader in a finally block so close() always frees
> the socket, while preserving the existing "Filesystem closed" exception
> behavior.
> Reporter: YUBI LEE
> Priority: Major
> Labels: pull-request-available
>
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