diff --git a/lib/private/Lock/MemcacheLockingProvider.php b/lib/private/Lock/MemcacheLockingProvider.php index 55a82b2278..4d1b3dc0bc 100644 --- a/lib/private/Lock/MemcacheLockingProvider.php +++ b/lib/private/Lock/MemcacheLockingProvider.php @@ -90,14 +90,20 @@ class MemcacheLockingProvider extends AbstractLockingProvider { */ public function releaseLock(string $path, int $type) { if ($type === self::LOCK_SHARED) { + $newValue = 0; if ($this->getOwnSharedLockCount($path) === 1) { $removed = $this->memcache->cad($path, 1); // if we're the only one having a shared lock we can remove it in one go if (!$removed) { //someone else also has a shared lock, decrease only - $this->memcache->dec($path); + $newValue = $this->memcache->dec($path); } } else { // if we own more than one lock ourselves just decrease - $this->memcache->dec($path); + $newValue = $this->memcache->dec($path); + } + + // if we somehow release more locks then exists, reset the lock + if ($newValue < 0) { + $this->memcache->cad($path, $newValue); } } else if ($type === self::LOCK_EXCLUSIVE) { $this->memcache->cad($path, 'exclusive'); diff --git a/tests/lib/Lock/LockingProvider.php b/tests/lib/Lock/LockingProvider.php index 49742baa56..9c0461e2e6 100644 --- a/tests/lib/Lock/LockingProvider.php +++ b/tests/lib/Lock/LockingProvider.php @@ -243,4 +243,16 @@ abstract class LockingProvider extends TestCase { $this->instance->acquireLock('foo', ILockingProvider::LOCK_SHARED); $this->instance->changeLock('foo', ILockingProvider::LOCK_SHARED); } + + public function testReleaseNonExistingShared() { + $this->instance->acquireLock('foo', ILockingProvider::LOCK_SHARED); + $this->instance->releaseLock('foo', ILockingProvider::LOCK_SHARED); + + // releasing a lock once to many should not result in a locked state + $this->instance->releaseLock('foo', ILockingProvider::LOCK_SHARED); + + $this->instance->acquireLock('foo', ILockingProvider::LOCK_EXCLUSIVE); + $this->assertTrue($this->instance->isLocked('foo', ILockingProvider::LOCK_EXCLUSIVE)); + $this->instance->releaseLock('foo', ILockingProvider::LOCK_EXCLUSIVE); + } }