get shared storage storage id without setting up the storage

apps/files_sharing/lib/SharedMount.php

@@ -235,4 +235,17 @@ class SharedMount extends MountPoint implements MoveableMount {
 	public function getStorageRootId() {
 		return $this->getShare()->getNodeId();
 	}
+
+	/**
+	 * @return int
+	 */
+	public function getNumericStorageId() {
+		$builder = \OC::$server->getDatabaseConnection()->getQueryBuilder();
+
+		$query = $builder->select('storage')
+			->from('filecache')
+			->where($builder->expr()->eq('fileid', $builder->createNamedParameter($this->getShare()->getNodeId())));
+
+		return $query->execute()->fetchColumn();
+	}
 }

lib/private/Files/Config/LazyStorageMountInfo.php

@@ -48,11 +48,7 @@ class LazyStorageMountInfo extends CachedMountInfo {
 	 */
 	public function getStorageId() {
 		if (!$this->storageId) {
-			$storage = $this->mount->getStorage();
-			if (!$storage) {
-				return -1;
-			}
-			$this->storageId = $storage->getStorageCache()->getNumericId();
+			$this->storageId = $this->mount->getNumericStorageId();
 		}
 		return parent::getStorageId();
 	}

lib/private/Files/Mount/MountPoint.php

@@ -191,6 +191,13 @@ class MountPoint implements IMountPoint {
 		return $this->storageId;
 	}
 
+	/**
+	 * @return int
+	 */
+	public function getNumericStorageId() {
+		return $this->getStorage()->getStorageCache()->getNumericId();
+	}
+
 	/**
 	 * @param string $path
 	 * @return string

lib/public/Files/Mount/IMountPoint.php

@@ -61,6 +61,14 @@ interface IMountPoint {
 	 */
 	public function getStorageId();
 
+	/**
+	 * Get the id of the storages
+	 *
+	 * @return int
+	 * @since 9.1.0
+	 */
+	public function getNumericStorageId();
+
 	/**
 	 * Get the path relative to the mountpoint
 	 *