Fix deadlock in timed write lock acquisition.

1 files changed, 20 insertions, 2 deletions

diff --git a/src/main/java/com/amazon/carbonado/repo/map/UpgradableLock.java b/src/main/java/com/amazon/carbonado/repo/map/UpgradableLock.java
index 55074e1..60c9bfa 100644
--- a/src/main/java/com/amazon/carbonado/repo/map/UpgradableLock.java
+++ b/src/main/java/com/amazon/carbonado/repo/map/UpgradableLock.java
@@ -469,8 +469,26 @@ class UpgradableLock<L> {
             throw new InterruptedException();

         }

         if (!tryLockForWrite(locker)) {

-            return lockForWriteQueuedInterruptibly(locker, addWriteWaiter(),

-                                                   unit.toNanos(timeout));

+            long start = System.nanoTime();

+            Result upgradeResult = tryLockForUpgrade_(locker, timeout, unit);

+            if (upgradeResult == Result.FAILED) {

+                return false;

+            }

+            if (!tryLockForWrite(locker)) {

+                if ((timeout = unit.toNanos(timeout) - (System.nanoTime() - start)) <= 0) {

+                    return false;

+                }

+                if (!lockForWriteQueuedInterruptibly(locker, addWriteWaiter(), timeout)) {

+                    return false;

+                }

+            }

+            if (upgradeResult == Result.ACQUIRED) {

+                // clear upgrade state bit to indicate automatic upgrade

+                while (!clearUpgradeLock(mState)) {}

+            } else {

+                // undo automatic upgrade count increment

+                mUpgradeCount--;

+            }

         }

         return true;

     }