Fix potential deadlock in levelsController compaction dgraph-io#1795

Signed-off-by: thomassong <thomassong2012@gmail.com>
mYmNeo · Jan 17, 2023 · d97b99c · d97b99c
1 parent 7c7dc31
commit d97b99c
Showing 1 changed file with 6 additions and 2 deletions.
diff --git a/levels.go b/levels.go
@@ -777,11 +777,15 @@ type compactDef struct {
 
 func (cd *compactDef) lockLevels() {
 	cd.thisLevel.RLock()
-	cd.nextLevel.RLock()
+	if cd.thisLevel.level != cd.nextLevel.level {
+		cd.nextLevel.RLock()
+	}
 }
 
 func (cd *compactDef) unlockLevels() {
-	cd.nextLevel.RUnlock()
+	if cd.thisLevel.level != cd.nextLevel.level {
+		cd.nextLevel.RUnlock()
+	}
 	cd.thisLevel.RUnlock()
 }