From 3f184dc28d1744bab131af067fe5c709659fb416 Mon Sep 17 00:00:00 2001
From: "Brian S. O'Neill" <bronee@gmail.com>
Date: Fri, 12 Dec 2008 23:42:13 +0000
Subject: Fix deadlock in timed write lock acquisition.
---
.../amazon/carbonado/repo/map/UpgradableLock.java | 22 ++++++++++++++++++++--
1 file changed, 20 insertions(+), 2 deletions(-)
(limited to 'src/main/java/com/amazon/carbonado/repo/map')
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;
}
--
cgit v1.2.3