diff --git a/fluss-common/src/main/java/org/apache/fluss/utils/FileLock.java b/fluss-common/src/main/java/org/apache/fluss/utils/FileLock.java index 0c73fffdc2..3c2c22b474 100644 --- a/fluss-common/src/main/java/org/apache/fluss/utils/FileLock.java +++ b/fluss-common/src/main/java/org/apache/fluss/utils/FileLock.java @@ -22,6 +22,7 @@ import java.io.File; import java.io.FileOutputStream; import java.io.IOException; +import java.nio.channels.OverlappingFileLockException; import java.nio.file.Path; import java.nio.file.Paths; @@ -70,8 +71,14 @@ private void init() throws IOException { * Try to acquire a lock on the locking file. This method immediately returns whenever the lock * is acquired or not. * + *

Returns {@code false} when the lock is already held (either by another process via {@link + * java.nio.channels.FileChannel#tryLock()} returning {@code null}, or by another lock in the + * same JVM signalled by {@link OverlappingFileLockException}). Genuine I/O failures are + * propagated to the caller instead of being silently swallowed, so they are not mistaken for a + * contended lock. + * * @return True if successfully acquired the lock - * @throws IOException If the file path is invalid + * @throws IOException If an I/O error occurs while acquiring the lock */ public boolean tryLock() throws IOException { if (outputStream == null) { @@ -79,8 +86,17 @@ public boolean tryLock() throws IOException { } try { lock = outputStream.getChannel().tryLock(); - } catch (Exception e) { + } catch (OverlappingFileLockException e) { + // Another lock in the same JVM already holds (or overlaps) this region; treat it as + // an unsuccessful attempt rather than an error, mirroring the FileChannel#tryLock + // contract for inter-process contention. return false; + } catch (IOException | RuntimeException e) { + // The FileOutputStream was opened by init() above; if acquiring the lock fails for + // any reason other than contention we must release it here, otherwise the underlying + // file descriptor leaks for the lifetime of the JVM. + closeOutputStreamQuietly(); + throw e; } return lock != null; @@ -106,21 +122,42 @@ public void unlock() throws IOException { */ public void unlockAndDestroy() throws IOException { try { - unlock(); - if (lock != null) { - lock.channel().close(); - lock = null; - } - if (outputStream != null) { - outputStream.close(); - outputStream = null; + try { + unlock(); + } finally { + try { + if (lock != null) { + lock.channel().close(); + lock = null; + } + } finally { + // Always close the output stream, even when releasing or closing the channel + // above threw; otherwise the file descriptor would leak whenever cleanup + // failed partway through. + if (outputStream != null) { + outputStream.close(); + outputStream = null; + } + } } - } finally { this.file.delete(); } } + private void closeOutputStreamQuietly() { + if (outputStream == null) { + return; + } + try { + outputStream.close(); + } catch (IOException ignored) { + // Best-effort cleanup; the original failure will be propagated by the caller. + } finally { + outputStream = null; + } + } + /** * Check whether a FileLock is actually holding the lock. * diff --git a/fluss-common/src/test/java/org/apache/fluss/utils/FileLockTest.java b/fluss-common/src/test/java/org/apache/fluss/utils/FileLockTest.java new file mode 100644 index 0000000000..d5adc88700 --- /dev/null +++ b/fluss-common/src/test/java/org/apache/fluss/utils/FileLockTest.java @@ -0,0 +1,115 @@ +/* + * 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.fluss.utils; + +import org.junit.jupiter.api.Test; +import org.junit.jupiter.api.io.TempDir; + +import java.io.File; +import java.nio.file.Path; + +import static org.assertj.core.api.Assertions.assertThat; +import static org.assertj.core.api.Assertions.assertThatThrownBy; + +/** Tests for {@link FileLock}. */ +class FileLockTest { + + @TempDir Path tempDir; + + @Test + void testTryLockAndUnlock() throws Exception { + File lockFile = tempDir.resolve("lock1").toFile(); + FileLock fileLock = new FileLock(lockFile.getAbsolutePath()); + + assertThat(fileLock.tryLock()).isTrue(); + assertThat(fileLock.isValid()).isTrue(); + assertThat(lockFile).exists(); + + fileLock.unlock(); + assertThat(fileLock.isValid()).isFalse(); + + fileLock.unlockAndDestroy(); + assertThat(lockFile).doesNotExist(); + } + + @Test + void testTryLockReturnsFalseOnSameJvmContention() throws Exception { + // Two FileLock instances in the same JVM target the same underlying file. The second + // attempt must return false instead of swallowing OverlappingFileLockException as an + // I/O failure or leaking a file descriptor. + File lockFile = tempDir.resolve("lockcontended").toFile(); + FileLock first = new FileLock(lockFile.getAbsolutePath()); + FileLock second = new FileLock(lockFile.getAbsolutePath()); + + try { + assertThat(first.tryLock()).isTrue(); + assertThat(second.tryLock()).isFalse(); + assertThat(second.isValid()).isFalse(); + } finally { + second.unlockAndDestroy(); + first.unlockAndDestroy(); + } + assertThat(lockFile).doesNotExist(); + } + + @Test + void testTryLockAfterUnlockAndDestroyIsReusable() throws Exception { + // After unlockAndDestroy() the internal output stream must be closed and reset so a + // subsequent tryLock() can re-initialize it without leaking the previous descriptor. + File lockFile = tempDir.resolve("lockreuse").toFile(); + FileLock fileLock = new FileLock(lockFile.getAbsolutePath()); + + assertThat(fileLock.tryLock()).isTrue(); + fileLock.unlockAndDestroy(); + assertThat(lockFile).doesNotExist(); + + // Reusing the same instance should transparently re-create the underlying file. + assertThat(fileLock.tryLock()).isTrue(); + assertThat(fileLock.isValid()).isTrue(); + fileLock.unlockAndDestroy(); + assertThat(lockFile).doesNotExist(); + } + + @Test + void testUnlockAndDestroyWithoutAcquiringLock() throws Exception { + // Calling unlockAndDestroy() without ever acquiring the lock must not throw and must + // leave no resources behind. + File lockFile = tempDir.resolve("lockneveracquired").toFile(); + FileLock fileLock = new FileLock(lockFile.getAbsolutePath()); + + fileLock.unlockAndDestroy(); + assertThat(fileLock.isValid()).isFalse(); + assertThat(lockFile).doesNotExist(); + } + + @Test + void testIsValidIsFalseBeforeTryLock() { + FileLock fileLock = new FileLock(tempDir.resolve("lockfresh").toString()); + assertThat(fileLock.isValid()).isFalse(); + } + + @Test + void testConstructorRejectsFileNameWithoutLegalCharacters() { + // The constructor strips everything outside [\w/\\] from the file name; a name made up + // entirely of illegal characters must fail fast rather than silently locking an empty + // path. + assertThatThrownBy(() -> new FileLock(tempDir.resolve("???").toString())) + .isInstanceOf(IllegalArgumentException.class) + .hasMessageContaining("legal characters"); + } +}