From 392df2eaf4ae41530b4743305a765a7ec173e92a Mon Sep 17 00:00:00 2001 From: Jaakko Salo Date: Sun, 24 May 2020 03:19:04 +0300 Subject: [PATCH] Fix releasing a shared lock multiple times Signed-off-by: Jaakko Salo --- lib/private/Lock/MemcacheLockingProvider.php | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/lib/private/Lock/MemcacheLockingProvider.php b/lib/private/Lock/MemcacheLockingProvider.php index 3d7510f43f..bff4eabbbd 100644 --- a/lib/private/Lock/MemcacheLockingProvider.php +++ b/lib/private/Lock/MemcacheLockingProvider.php @@ -94,8 +94,12 @@ class MemcacheLockingProvider extends AbstractLockingProvider { */ public function releaseLock(string $path, int $type) { if ($type === self::LOCK_SHARED) { + $ownSharedLockCount = $this->getOwnSharedLockCount($path); $newValue = 0; - if ($this->getOwnSharedLockCount($path) === 1) { + if ($ownSharedLockCount === 0) { // if we are not holding the lock, don't try to release it + return; + } + if ($ownSharedLockCount === 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 $newValue = $this->memcache->dec($path);