use and cache root storage info if a share can't be resolved

as is a broken share will never be cached

Signed-off-by: Robin Appelman <robin@icewind.nl>

lib/private/legacy/OC_Helper.php

@@ -48,6 +48,7 @@ use OC\Files\Filesystem;
 use OCP\Files\Mount\IMountPoint;
 use OCP\ICacheFactory;
 use OCP\IUser;
+use Psr\Log\LoggerInterface;
 use Symfony\Component\Process\ExecutableFinder;
 
 /**
@@ -518,7 +519,6 @@ class OC_Helper {
 		$sourceStorage = $storage;
 		if ($storage->instanceOfStorage('\OCA\Files_Sharing\SharedStorage')) {
 			$includeExtStorage = false;
-			$sourceStorage = $storage->getSourceStorage();
 			$internalPath = $storage->getUnjailedPath($rootInfo->getInternalPath());
 		} else {
 			$internalPath = $rootInfo->getInternalPath();
@@ -544,7 +544,19 @@ class OC_Helper {
 			/** @var \OC\Files\Storage\Wrapper\Quota $storage */
 			$quota = $sourceStorage->getQuota();
 		}
-		$free = $sourceStorage->free_space($internalPath);
+		try {
+			$free = $sourceStorage->free_space($internalPath);
+		} catch (\Exception $e) {
+			if ($path === "") {
+				throw $e;
+			}
+			/** @var LoggerInterface $logger */
+			$logger = \OC::$server->get(LoggerInterface::class);
+			$logger->warning("Error while getting quota info, using root quota", ['exception' => $e]);
+			$rootInfo = self::getStorageInfo("");
+			$memcache->set($cacheKey, $rootInfo, 5 * 60);
+			return $rootInfo;
+		}
 		if ($free >= 0) {
 			$total = $free + $used;
 		} else {