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fix(lock): keep first saved TTL across nested shared locks #66165

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fix(lock): keep first saved TTL across nested shared locks #66165

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10 changes: 6 additions & 4 deletions lib/private/Lock/MemcacheLockingProvider.php
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Original file line number Diff line number Diff line change
Expand Up @@ -64,10 +64,12 @@ public function isLocked(string $path, int $type): bool {
public function acquireLock(string $path, int $type, ?string $readablePath = null): void {
if ($type === self::LOCK_SHARED) {
// save the old TTL to for `restoreTTL`
$this->oldTTLs[$path] = [
'ttl' => $this->getTTL($path),
'time' => $this->timeFactory->getTime()
];
if ($this->getOwnSharedLockCount($path) === 0) {
$this->oldTTLs[$path] = [
'ttl' => $this->getTTL($path),
'time' => $this->timeFactory->getTime()
];
}
if (!$this->memcache->inc($path)) {
throw new LockedException($path, null, $this->getExistingLockForException($path), $readablePath);
}
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56 changes: 56 additions & 0 deletions tests/lib/Lock/MemcacheLockingProviderTest.php
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Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,9 @@
use OC\Memcache\ArrayCache;
use OCP\AppFramework\Utility\ITimeFactory;
use OCP\IMemcache;
use OCP\IMemcacheTTL;
use OCP\Lock\ILockingProvider;
use OCP\Lock\LockedException;
use OCP\Server;

class MemcacheLockingProviderTest extends LockingProvider {
Expand All @@ -21,6 +23,8 @@ class MemcacheLockingProviderTest extends LockingProvider {
*/
private $memcache;

private int $now = 0;

/**
* @return ILockingProvider
*/
Expand All @@ -36,4 +40,56 @@ protected function tearDown(): void {
$this->memcache->clear();
parent::tearDown();
}

public function testFailedExclusiveLockRestoresTTLAfterNestedSharedLock(): void {
$timeFactory = $this->createMock(ITimeFactory::class);
$timeFactory->method('getTime')
->willReturnCallback(fn () => $this->now);
$memcache = new class($timeFactory) extends ArrayCache implements IMemcacheTTL {
private array $expires = [];

public function __construct(
private ITimeFactory $timeFactory,
) {
parent::__construct();
}

#[\Override]
public function setTTL(string $key, int $ttl) {
$this->expires[$key] = $this->timeFactory->getTime() + $ttl;
}

#[\Override]
public function getTTL(string $key): int|false {
return isset($this->expires[$key]) ? $this->expires[$key] - $this->timeFactory->getTime() : false;
}

#[\Override]
public function compareSetTTL(string $key, $value, int $ttl): bool {
if ($this->get($key) !== $value) {
return false;
}
$this->setTTL($key, $ttl);
return true;
}
};

$this->now = 1000;
$leaked = new MemcacheLockingProvider($memcache, $timeFactory);
$leaked->acquireLock('foo', ILockingProvider::LOCK_SHARED);

$this->now = 2000;
$provider = new MemcacheLockingProvider($memcache, $timeFactory);
$provider->acquireLock('foo', ILockingProvider::LOCK_SHARED);
$provider->acquireLock('foo', ILockingProvider::LOCK_SHARED);
$provider->releaseLock('foo', ILockingProvider::LOCK_SHARED);
try {
$provider->changeLock('foo', ILockingProvider::LOCK_EXCLUSIVE);
$this->fail('Expected LockedException');
} catch (LockedException) {
}
$provider->releaseLock('foo', ILockingProvider::LOCK_SHARED);

$this->assertEquals(2600, $memcache->getTTL('foo'));
}
}