confirm won't blocking other thread

redis · Aug 16, 2024 · c3db27f · c3db27f
1 parent a59045a
commit c3db27f
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Showing 2 changed files with 20 additions and 1 deletion.
diff --git a/src/main/java/io/lettuce/core/protocol/SharedLock.java b/src/main/java/io/lettuce/core/protocol/SharedLock.java
@@ -146,9 +146,13 @@ private void lockWritersExclusive() {
     private void unlockWritersExclusive() {
 
         if (exclusiveLockOwner == Thread.currentThread()) {
+            // check exclusive look not reentrant first
             if (WRITERS.compareAndSet(this, -1, sharedCnt.get())) {
                 exclusiveLockOwner = null;
+                return;
             }
+            // otherwise unlock until no more reentrant left
+            WRITERS.incrementAndGet(this);
         }
     }
 

diff --git a/src/test/java/io/lettuce/core/protocol/SharedLockTest.java b/src/test/java/io/lettuce/core/protocol/SharedLockTest.java
@@ -27,7 +27,8 @@ public void safety_on_reentrant_lock_exclusive_on_writers() throws InterruptedEx
             sharedLock.decrementWriters();
         }
 
-        cnt.await(1, TimeUnit.SECONDS);
+        boolean await = cnt.await(1, TimeUnit.SECONDS);
+        Assertions.assertTrue(await);
 
         // verify writers won't be negative after finally decrementWriters
         String result = sharedLock.doExclusive(() -> {
@@ -37,6 +38,20 @@ public void safety_on_reentrant_lock_exclusive_on_writers() throws InterruptedEx
         });
 
         Assertions.assertEquals("ok", result);
+
+        // and other writers should be passed after exclusive lock released
+        CountDownLatch cntOtherThread = new CountDownLatch(1);
+        new Thread(() -> {
+            try {
+                sharedLock.incrementWriters();
+                cntOtherThread.countDown();
+            } finally {
+                sharedLock.decrementWriters();
+            }
+        }).start();
+
+        await = cntOtherThread.await(1, TimeUnit.SECONDS);
+        Assertions.assertTrue(await);
     }
 
 }