diff --git a/apps/comments/appinfo/app.php b/apps/comments/appinfo/app.php
index b491b1d4d3f0..bbc292dc4a1f 100644
--- a/apps/comments/appinfo/app.php
+++ b/apps/comments/appinfo/app.php
@@ -54,7 +54,7 @@ function () {
 
 $eventDispatcher->addListener(\OCP\Comments\CommentsEntityEvent::EVENT_ENTITY, function (\OCP\Comments\CommentsEntityEvent $event) {
 	$event->addEntityCollection('files', function ($name) {
-		$nodes = \OC::$server->getUserFolder()->getById(\intval($name));
+		$nodes = \OC::$server->getUserFolder()->getById((int)$name, true);
 		return !empty($nodes);
 	});
 });
diff --git a/apps/comments/lib/Activity/Listener.php b/apps/comments/lib/Activity/Listener.php
index a4ca3b4aa463..1781286713d9 100644
--- a/apps/comments/lib/Activity/Listener.php
+++ b/apps/comments/lib/Activity/Listener.php
@@ -86,10 +86,9 @@ public function commentEvent(CommentsEvent $event) {
 		foreach ($mounts as $mount) {
 			$owner = $mount->getUser()->getUID();
 			$ownerFolder = $this->rootFolder->getUserFolder($owner);
-			$nodes = $ownerFolder->getById($event->getComment()->getObjectId());
-			if (!empty($nodes)) {
-				/** @var Node $node */
-				$node = \array_shift($nodes);
+			$nodes = $ownerFolder->getById($event->getComment()->getObjectId(), true);
+			$node = $nodes[0] ?? null;
+			if ($node) {
 				$path = $node->getPath();
 				if (\strpos($path, '/' . $owner . '/files/') === 0) {
 					$path = \substr($path, \strlen('/' . $owner . '/files'));
diff --git a/apps/comments/tests/unit/ActivityListenerTest.php b/apps/comments/tests/unit/ActivityListenerTest.php
new file mode 100644
index 000000000000..6f81cc1da7d6
--- /dev/null
+++ b/apps/comments/tests/unit/ActivityListenerTest.php
@@ -0,0 +1,151 @@
+<?php
+/**
+ * @author Vincent Petry <pvince81@owncloud.com>
+ *
+ * @copyright Copyright (c) 2018, ownCloud GmbH
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OCA\Comments\Tests\unit;
+
+use OCA\Comments\Activity\Listener;
+use OCP\Comments\CommentsEntityEvent;
+use Test\Traits\UserTrait;
+use OCP\IUserSession;
+use OCP\Activity\IManager;
+use OCP\App\IAppManager;
+use OCP\Files\Config\IMountProviderCollection;
+use OCP\Files\IRootFolder;
+use OCP\Files\Config\IUserMountCache;
+use OCP\Files\Config\ICachedMountInfo;
+use OCP\IUser;
+use OCP\Files\Folder;
+use OCP\Activity\IEvent;
+use OCA\Comments\Activity\Extension;
+use OCP\Comments\IComment;
+use OCP\Comments\CommentsEvent;
+
+/**
+ * Tests for the activity listener
+ *
+ * @group DB
+ */
+class ActivityListenerTest extends \Test\TestCase {
+	use UserTrait;
+
+	/**
+	 * @var Listener
+	 */
+	private $listener;
+
+	/**
+	 * @var IUserMountCache
+	 */
+	private $userMountCache;
+
+	/**
+	 * @var IRootFolder
+	 */
+	private $rootFolder;
+
+	/**
+	 * @var IUserSession
+	 */
+	private $userSession;
+
+	/**
+	 * @var IManager
+	 */
+	private $activityManager;
+
+	protected function setUp() {
+		parent::setUp();
+
+		$this->activityManager = $this->createMock(IManager::class);
+		$this->userSession = $this->createMock(IUserSession::class);
+		$appManager = $this->createMock(IAppManager::class);
+		$appManager->method('isInstalled')->with('activity')->willReturn(true);
+
+		$this->userMountCache = $this->createMock(IUserMountCache::class);
+
+		$mountProviderCollection = $this->createMock(IMountProviderCollection::class);
+		$mountProviderCollection->method('getMountCache')->willReturn($this->userMountCache);
+
+		$this->rootFolder = $this->createMock(IRootFolder::class);
+
+		// needed for the one unmockable static method "Share::getUsersSharingFile"...
+		$this->createUser('user1');
+		$this->createUser('actor1');
+
+		$this->listener = new Listener(
+			$this->activityManager,
+			$this->userSession,
+			$appManager,
+			$mountProviderCollection,
+			$this->rootFolder
+		);
+	}
+
+	public function testActivityOnFilesComment() {
+		$user = $this->createMock(IUser::class);
+		$user->method('getUID')->willReturn('user1');
+
+		$actor = $this->createMock(IUser::class);
+		$actor->method('getUID')->willReturn('actor1');
+
+		$this->userSession->method('getUser')->willReturn($actor);
+
+		$cachedMountInfo = $this->createMock(ICachedMountInfo::class);
+		$cachedMountInfo->method('getUser')->willReturn($user);
+
+		$node = $this->createMock(Folder::class);
+		$node->method('getPath')->willReturn('/user1/files/folder');
+
+		$ownerFolder = $this->createMock(Folder::class);
+		$ownerFolder->method('getById')
+			->with(123, true)
+			->willReturn([$node]);
+
+		$this->rootFolder->method('getUserFolder')
+			->with('user1')
+			->willReturn($ownerFolder);
+
+		$this->userMountCache->method('getMountsForFileId')
+			->with(123)
+			->willReturn([$cachedMountInfo]);
+
+		$activityEvent = $this->createMock(IEvent::class);
+		$activityEvent->expects($this->once())->method('setApp')->with('comments')->willReturn($activityEvent);
+		$activityEvent->expects($this->once())->method('setType')->with('comments')->willReturn($activityEvent);
+		$activityEvent->expects($this->once())->method('setAuthor')->with('actor1')->willReturn($activityEvent);
+		$activityEvent->expects($this->once())->method('setObject')->with('files', 123)->willReturn($activityEvent);
+		$activityEvent->expects($this->once())->method('setMessage')->with(Extension::ADD_COMMENT_MESSAGE, [111])->willReturn($activityEvent);
+
+		$this->activityManager->method('generateEvent')
+			->willReturn($activityEvent);
+		$this->activityManager->expects($this->once())
+			->method('publish')
+			->with($activityEvent);
+
+		$comment = $this->createMock(IComment::class);
+		$comment->method('getObjectType')->willReturn('files');
+		$comment->method('getObjectId')->willReturn(123);
+		$comment->method('getId')->willReturn(111);
+
+		$commentsEvent = new CommentsEvent(CommentsEvent::EVENT_ADD, $comment);
+		$this->listener->commentEvent($commentsEvent);
+	}
+}
diff --git a/apps/dav/lib/Connector/Sabre/FilesReportPlugin.php b/apps/dav/lib/Connector/Sabre/FilesReportPlugin.php
index 3ea18fabfb0d..e6512b376aaf 100644
--- a/apps/dav/lib/Connector/Sabre/FilesReportPlugin.php
+++ b/apps/dav/lib/Connector/Sabre/FilesReportPlugin.php
@@ -360,9 +360,9 @@ public function findNodesByFileIds($rootNode, $fileIds) {
 
 		$results = [];
 		foreach ($fileIds as $fileId) {
-			$entry = $folder->getById($fileId);
+			$entries = $folder->getById($fileId, true);
+			$entry = $entries[0] ?? null;
 			if ($entry) {
-				$entry = \current($entry);
 				$node = $this->makeSabreNode($entry);
 				if ($node) {
 					$results[] = $node;
diff --git a/apps/dav/lib/RootCollection.php b/apps/dav/lib/RootCollection.php
index faa8e3fba63d..43eb9b178c03 100644
--- a/apps/dav/lib/RootCollection.php
+++ b/apps/dav/lib/RootCollection.php
@@ -74,7 +74,7 @@ public function __construct() {
 			\OC::$server->getSystemTagObjectMapper(),
 			\OC::$server->getUserSession(),
 			\OC::$server->getGroupManager(),
-			\OC::$server->getRootFolder()
+			\OC::$server->getLazyRootFolder()
 		);
 
 		$usersCardDavBackend = new CardDavBackend($db, $userPrincipalBackend, $groupPrincipalBackend, $dispatcher);
@@ -109,7 +109,7 @@ public function __construct() {
 				$systemTagRelationsCollection,
 				$uploadCollection,
 				$avatarCollection,
-				new \OCA\DAV\Meta\RootCollection(\OC::$server->getRootFolder()),
+				new \OCA\DAV\Meta\RootCollection(\OC::$server->getLazyRootFolder()),
 				$queueCollection
 		];
 
diff --git a/apps/dav/lib/SystemTag/SystemTagsObjectTypeCollection.php b/apps/dav/lib/SystemTag/SystemTagsObjectTypeCollection.php
index fa44c0b2f47b..4ffd4aa20d14 100644
--- a/apps/dav/lib/SystemTag/SystemTagsObjectTypeCollection.php
+++ b/apps/dav/lib/SystemTag/SystemTagsObjectTypeCollection.php
@@ -139,7 +139,7 @@ public function childExists($name) {
 		if ($this->objectType === 'files') {
 			// make sure the object is reachable for the current user
 			$userId = $this->userSession->getUser()->getUID();
-			$nodes = $this->fileRoot->getUserFolder($userId)->getById(\intval($name));
+			$nodes = $this->fileRoot->getUserFolder($userId)->getById((int)$name, true);
 			return !empty($nodes);
 		}
 		return true;
diff --git a/apps/federatedfilesharing/lib/FederatedShareProvider.php b/apps/federatedfilesharing/lib/FederatedShareProvider.php
index c6bea791e61a..01606ce5097a 100644
--- a/apps/federatedfilesharing/lib/FederatedShareProvider.php
+++ b/apps/federatedfilesharing/lib/FederatedShareProvider.php
@@ -886,7 +886,7 @@ private function getNode($userId, $id) {
 			throw new InvalidShare();
 		}
 
-		$nodes = $userFolder->getById($id);
+		$nodes = $userFolder->getById($id, true);
 
 		if (empty($nodes)) {
 			throw new InvalidShare();
diff --git a/apps/federatedfilesharing/tests/FederatedShareProviderTest.php b/apps/federatedfilesharing/tests/FederatedShareProviderTest.php
index 8b0189c4be0c..ffb0fbd6574c 100644
--- a/apps/federatedfilesharing/tests/FederatedShareProviderTest.php
+++ b/apps/federatedfilesharing/tests/FederatedShareProviderTest.php
@@ -37,6 +37,8 @@
 use OCP\IUserManager;
 use OCP\Share\IManager;
 use OCP\Share\IShare;
+use OCP\Files\Folder;
+use OCP\IUser;
 
 /**
  * Class FederatedShareProviderTest
@@ -188,6 +190,90 @@ public function testCreate() {
 		$this->assertEquals('token', $share->getToken());
 	}
 
+	public function testCreateLegacy() {
+		$share = $this->shareManager->newShare();
+
+		$node = $this->createMock('\OCP\Files\File');
+		$node->method('getId')->willReturn(42);
+		$node->method('getName')->willReturn('myFile');
+
+		$share->setSharedWith('user@server.com')
+			->setShareOwner('shareOwner')
+			->setPermissions(19)
+			->setNode($node);
+
+		$this->tokenHandler->method('generateToken')->willReturn('token');
+
+		$shareWithAddress = new Address('user@server.com');
+		$ownerAddress = new Address('shareOwner@http://localhost/');
+		$sharedByAddress = new Address('sharedBy@http://localhost/');
+		$this->addressHandler->expects($this->any())->method('getLocalUserFederatedAddress')
+			->will($this->onConsecutiveCalls($ownerAddress, $sharedByAddress, $ownerAddress));
+
+		$this->addressHandler->expects($this->any())->method('splitUserRemote')
+			->willReturn(['user', 'server.com']);
+
+		$this->notifications->expects($this->once())
+			->method('sendRemoteShare')
+			->with(
+				$this->equalTo($shareWithAddress),
+				$this->equalTo($ownerAddress),
+				$this->equalTo($sharedByAddress),
+				$this->equalTo('token'),
+				$this->equalTo('myFile'),
+				$this->anything()
+			)->willReturn(true);
+
+		$folderOwner = $this->createMock(IUser::class);
+		$folderOwner->method('getUID')->willReturn('folderOwner');
+		$node = $this->createMock(Folder::class);
+		$node->method('getOwner')->willReturn($folderOwner);
+
+		$userFolder = $this->createMock(Folder::class);
+		$userFolder->method('getById')
+			->with(42, true)
+			->willReturn([$node]);
+		$this->rootFolder->expects($this->once())
+			->method('getUserFolder')
+			->with('shareOwner')
+			->willReturn($userFolder);
+
+		$share = $this->provider->create($share);
+
+		$qb = $this->connection->getQueryBuilder();
+		$stmt = $qb->select('*')
+			->from('share')
+			->where($qb->expr()->eq('id', $qb->createNamedParameter($share->getId())))
+			->execute();
+
+		$data = $stmt->fetch();
+		$stmt->closeCursor();
+
+		$expected = [
+			'share_type' => \OCP\Share::SHARE_TYPE_REMOTE,
+			'share_with' => 'user@server.com',
+			'uid_owner' => 'shareOwner',
+			'uid_initiator' => null,
+			'item_type' => 'file',
+			'item_source' => 42,
+			'file_source' => 42,
+			'permissions' => 19,
+			'accepted' => 0,
+			'token' => 'token',
+		];
+		$this->assertArraySubset($expected, $data);
+
+		$this->assertEquals($data['id'], $share->getId());
+		$this->assertEquals(\OCP\Share::SHARE_TYPE_REMOTE, $share->getShareType());
+		$this->assertEquals('user@server.com', $share->getSharedWith());
+		$this->assertEquals('shareOwner', $share->getSharedBy());
+		$this->assertEquals('folderOwner', $share->getShareOwner());
+		$this->assertEquals('file', $share->getNodeType());
+		$this->assertEquals(42, $share->getNodeId());
+		$this->assertEquals(19, $share->getPermissions());
+		$this->assertEquals('token', $share->getToken());
+	}
+
 	public function testCreateCouldNotFindServer() {
 		$share = $this->shareManager->newShare();
 
diff --git a/apps/files/lib/ActivityHelper.php b/apps/files/lib/ActivityHelper.php
index 20ac77cbc75a..c198c10353cb 100644
--- a/apps/files/lib/ActivityHelper.php
+++ b/apps/files/lib/ActivityHelper.php
@@ -59,10 +59,9 @@ public function getFavoriteFilePaths($user) {
 		$rootFolder = \OC::$server->getUserFolder($user);
 		$folders = $items = [];
 		foreach ($favorites as $favorite) {
-			$nodes = $rootFolder->getById($favorite);
-			if (!empty($nodes)) {
-				/** @var \OCP\Files\Node $node */
-				$node = \array_shift($nodes);
+			$nodes = $rootFolder->getById($favorite, true);
+			$node = $nodes[0] ?? null;
+			if ($node) {
 				$path = \substr($node->getPath(), \strlen($user . '/files/'));
 
 				$items[] = $path;
diff --git a/apps/files/tests/ActivityHelperTest.php b/apps/files/tests/ActivityHelperTest.php
new file mode 100644
index 000000000000..e2c04ea276e8
--- /dev/null
+++ b/apps/files/tests/ActivityHelperTest.php
@@ -0,0 +1,137 @@
+<?php
+/**
+ * @author Vincent Petry <pvince81@owncloud.com>
+ *
+ * @copyright Copyright (c) 2018, ownCloud GmbH
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+use OCA\Files\ActivityHelper;
+use OCP\ITagManager;
+use OCP\ITags;
+use Test\Traits\UserTrait;
+
+/**
+ * Class ActivityHelperTest
+ *
+ * @group DB
+ */
+class ActivityHelperTest extends \Test\TestCase {
+	use UserTrait;
+
+	/**
+	 * @var ITagManager
+	 */
+	private $tagManager;
+
+	/**
+	 * @var ITags
+	 */
+	private $tags;
+
+	/**
+	 * @var ActivityHelper
+	 */
+	private $helper;
+
+	/**
+	 * @var string
+	 */
+	private $user;
+
+	protected function setUp() {
+		parent::setUp();
+
+		$this->tags = $this->createMock(ITags::class);
+
+		$this->user = $this->getUniqueID('files_activityhelpertest_user_');
+
+		// because \OC::$server->getUserFolder()
+		$this->createUser($this->user);
+		$this->loginAsUser($this->user);
+
+		$this->tagManager = $this->createMock(ITagManager::class);
+		$this->tagManager->expects($this->once())
+			->method('load')
+			->with('files', [], false, $this->user)
+			->willReturn($this->tags);
+
+		$this->helper = new ActivityHelper($this->tagManager);
+	}
+
+	/**
+	 * @expectedException \RuntimeException
+	 * @expectedExceptionMessage No favorites
+	 */
+	public function testGetFavoriteFilePathsNoFavorites() {
+		$this->tags->method('getFavorites')->willReturn([]);
+		$this->helper->getFavoriteFilePaths($this->user);
+	}
+
+	/**
+	 * @expectedException \RuntimeException
+	 * @expectedExceptionMessage Too many favorites
+	 */
+	public function testGetFavoriteFilePathsTooManyFavorites() {
+		$tooManyFavorites = [];
+		for ($i = 0; $i < ActivityHelper::FAVORITE_LIMIT + 1; $i++) {
+			$tooManyFavorites[] = [];
+		}
+
+		$this->tags->method('getFavorites')->willReturn($tooManyFavorites);
+
+		$this->helper->getFavoriteFilePaths($this->user);
+	}
+
+	public function testGetFavoriteFilePaths() {
+		$userFolder = \OC::$server->getUserFolder();
+		$fav1 = $userFolder->newFolder('fav1');
+		$fav2 = $userFolder->newFile('fav2.txt');
+		$userFolder->newFolder('nonfav1');
+		$userFolder->newFolder('nonfav2');
+
+		$favorites = [
+			$fav1->getId(),
+			$fav2->getId(),
+			$fav2->getId() + 999, // non-existing
+		];
+
+		$this->tags->method('getFavorites')->willReturn($favorites);
+
+		$result = $this->helper->getFavoriteFilePaths($this->user);
+
+		$this->assertEquals(['/fav1', '/fav2.txt'], $result['items']);
+		$this->assertEquals(['/fav1'], $result['folders']);
+	}
+
+	/**
+	 * @expectedException \RuntimeException
+	 * @expectedExceptionMessage No favorites
+	 */
+	public function testGetFavoriteFilePathsMissingFolder() {
+		$userFolder = \OC::$server->getUserFolder();
+		$aFolder = $userFolder->newFolder('x');
+
+		$favorites = [
+			// non-existing
+			$aFolder->getId() + 999,
+		];
+
+		$this->tags->method('getFavorites')->willReturn($favorites);
+
+		$result = $this->helper->getFavoriteFilePaths($this->user);
+	}
+}
diff --git a/apps/files_sharing/lib/Controller/Share20OcsController.php b/apps/files_sharing/lib/Controller/Share20OcsController.php
index bde1320991ef..8d1ee1c7645a 100644
--- a/apps/files_sharing/lib/Controller/Share20OcsController.php
+++ b/apps/files_sharing/lib/Controller/Share20OcsController.php
@@ -166,14 +166,12 @@ protected function formatShare(IShare $share, $received = false) {
 			$userFolder = $this->rootFolder->getUserFolder($this->currentUser->getUID());
 		}
 
-		$nodes = $userFolder->getById($share->getNodeId());
-
-		if (empty($nodes)) {
+		$nodes = $userFolder->getById($share->getNodeId(), true);
+		$node = $nodes[0] ?? null;
+		if ($node === null) {
 			throw new NotFoundException();
 		}
 
-		$node = $nodes[0];
-
 		$result['path'] = $userFolder->getRelativePath($node->getPath());
 		if ($node instanceof \OCP\Files\Folder) {
 			$result['item_type'] = 'folder';
@@ -912,8 +910,8 @@ public function notifyRecipients($itemSource, $shareType, $recipient) {
 		);
 
 		$userFolder = $this->rootFolder->getUserFolder($this->currentUser->getUID());
-		$nodes = $userFolder->getById($itemSource);
-		$node = $nodes[0];
+		$nodes = $userFolder->getById($itemSource, true);
+		$node = $nodes[0] ?? null;
 		$result = $mailNotification->sendInternalShareMail($node, $shareType, $recipientList);
 
 		// if we were able to send to at least one recipient, mark as sent
@@ -950,8 +948,8 @@ public function notifyRecipients($itemSource, $shareType, $recipient) {
 	 */
 	public function notifyRecipientsDisabled($itemSource, $shareType, $recipient) {
 		$userFolder = $this->rootFolder->getUserFolder($this->currentUser->getUID());
-		$nodes = $userFolder->getById($itemSource);
-		$node = $nodes[0];
+		$nodes = $userFolder->getById($itemSource, true);
+		$node = $nodes[0] ?? null;
 
 		$items = $this->shareManager->getSharedWith($recipient, $shareType, $node);
 		if (\count($items) > 0) {
diff --git a/apps/files_sharing/lib/SharedMount.php b/apps/files_sharing/lib/SharedMount.php
index 3923c58da4e1..059687095d97 100644
--- a/apps/files_sharing/lib/SharedMount.php
+++ b/apps/files_sharing/lib/SharedMount.php
@@ -193,13 +193,13 @@ public function isTargetAllowed($target) {
 			$fileId = (int)$targetStorage->getCache()->getId(\dirname($targetInternalPath));
 		}
 
-		$targetNodes = \OC::$server->getRootFolder()->getById($fileId);
-		if (empty($targetNodes)) {
+		$targetNodes = \OC::$server->getRootFolder()->getById($fileId, true);
+		$targetNode = $targetNodes[0] ?? null;
+		if ($targetNode === null) {
 			return false;
 		}
 
 		$shareManager = \OC::$server->getShareManager();
-		$targetNode = $targetNodes[0];
 		// FIXME: make it stop earlier in '/$userId/files'
 		while ($targetNode !== null && $targetNode->getPath() !== '/') {
 			$shares = $shareManager->getSharesByPath($targetNode);
diff --git a/apps/systemtags/lib/Activity/Listener.php b/apps/systemtags/lib/Activity/Listener.php
index 112ab4a8fcf9..3cbd9223235a 100644
--- a/apps/systemtags/lib/Activity/Listener.php
+++ b/apps/systemtags/lib/Activity/Listener.php
@@ -159,16 +159,15 @@ public function mapperEvent(MapperEvent $event) {
 		foreach ($mounts as $mount) {
 			$owner = $mount->getUser()->getUID();
 			$ownerFolder = $this->rootFolder->getUserFolder($owner);
-			$nodes = $ownerFolder->getById($event->getObjectId());
-			if (!empty($nodes)) {
-				/** @var Node $node */
-				$node = \array_shift($nodes);
+			$nodes = $ownerFolder->getById($event->getObjectId(), true);
+			$node = $nodes[0] ?? null;
+			if ($node) {
 				$path = $node->getPath();
 				if (\strpos($path, '/' . $owner . '/files/') === 0) {
 					$path = \substr($path, \strlen('/' . $owner . '/files'));
 				}
 				// Get all users that have access to the mount point
-				$users = \array_merge($users, Share::getUsersSharingFile($path, $owner, true, true));
+				$users = \array_merge($users, $this->getUsersSharingFile($path, $owner));
 			}
 		}
 
@@ -227,4 +226,8 @@ protected function prepareTagAsParameter(ISystemTag $tag) {
 			return '{{{' . $tag->getName() . '|||assignable}}}';
 		}
 	}
+
+	public function getUsersSharingFile($path, $owner) {
+		return Share::getUsersSharingFile($path, $owner, true, true);
+	}
 }
diff --git a/apps/systemtags/tests/ListenerTest.php b/apps/systemtags/tests/ListenerTest.php
deleted file mode 100644
index aad3e3c4c2b7..000000000000
--- a/apps/systemtags/tests/ListenerTest.php
+++ /dev/null
@@ -1,84 +0,0 @@
-<?php
-/**
- * @author Sujith Haridasan <sharidasan@owncloud.com>
- *
- * @copyright Copyright (c) 2018, ownCloud GmbH
- * @license AGPL-3.0
- *
- * This code is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License, version 3,
- * as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU Affero General Public License for more details.
- *
- * You should have received a copy of the GNU Affero General Public License, version 3,
- * along with this program.  If not, see <http://www.gnu.org/licenses/>
- *
- */
-
-namespace OCA\SystemTags\Tests;
-
-use OC\SystemTag\SystemTag;
-use OCA\SystemTags\Activity\Listener;
-use OCP\Activity\IManager;
-use OCP\App\IAppManager;
-use OCP\Files\Config\IMountProviderCollection;
-use OCP\Files\IRootFolder;
-use OCP\IGroupManager;
-use OCP\IUserSession;
-use OCP\SystemTag\ISystemTagManager;
-use Test\TestCase;
-
-class ListenerTest extends TestCase {
-	/** @var IGroupManager | \PHPUnit_Framework_MockObject_MockObject */
-	private $groupManager;
-	/** @var IManager | \PHPUnit_Framework_MockObject_MockObject */
-	private $activityManager;
-	/** @var IUserSession | \PHPUnit_Framework_MockObject_MockObject */
-	private $userSession;
-	/** @var ISystemTagManager | \PHPUnit_Framework_MockObject_MockObject */
-	private $tagManager;
-	/** @var IAppManager | \PHPUnit_Framework_MockObject_MockObject */
-	private $appManager;
-	/** @var IMountProviderCollection | \PHPUnit_Framework_MockObject_MockObject */
-	private $mountCollection;
-	/** @var IRootFolder | \PHPUnit_Framework_MockObject_MockObject */
-	private $rootFolder;
-	/** @var Listener */
-	private $listener;
-
-	public function setUp() {
-		parent::setUp();
-
-		$this->groupManager = $this->createMock(IGroupManager::class);
-		$this->activityManager = $this->createMock(IManager::class);
-		$this->userSession = $this->createMock(IUserSession::class);
-		$this->tagManager = $this->createMock(ISystemTagManager::class);
-		$this->appManager = $this->createMock(IAppManager::class);
-		$this->mountCollection = $this->createMock(IMountProviderCollection::class);
-		$this->rootFolder = $this->createMock(IRootFolder::class);
-		$this->listener = new Listener($this->groupManager, $this->activityManager,
-			$this->userSession, $this->tagManager, $this->appManager,
-			$this->mountCollection, $this->rootFolder);
-	}
-
-	public function prepareTagAsParameterProvider() {
-		return [
-			[new SystemTag('1', 'visibleTag', true, true, true), "{{{visibleTag|||assignable}}}"],
-			[new SystemTag('2', 'invisibleTag', false, false, false), "{{{invisibleTag|||invisible}}}"],
-			[new SystemTag('3', 'restrictTag', true, false, false), "{{{restrictTag|||not-assignable}}}"],
-			[new SystemTag('3', 'staticTag', true, true, false), "{{{staticTag|||not-editable}}}"],
-		];
-	}
-
-	/**
-	 * @dataProvider prepareTagAsParameterProvider
-	 */
-	public function testPrepareTagAsParameter(SystemTag $tag, $expectedResult) {
-		$result = $this->invokePrivate($this->listener, 'prepareTagAsParameter', [$tag]);
-		$this->assertEquals($expectedResult, $result);
-	}
-}
diff --git a/apps/systemtags/tests/ExtensionTest.php b/apps/systemtags/tests/unit/activity/ExtensionTest.php
similarity index 100%
rename from apps/systemtags/tests/ExtensionTest.php
rename to apps/systemtags/tests/unit/activity/ExtensionTest.php
diff --git a/apps/systemtags/tests/unit/activity/ListenerTest.php b/apps/systemtags/tests/unit/activity/ListenerTest.php
new file mode 100644
index 000000000000..1ecc2df62897
--- /dev/null
+++ b/apps/systemtags/tests/unit/activity/ListenerTest.php
@@ -0,0 +1,218 @@
+<?php
+/**
+ * @author Vincent Petry <pvince81@owncloud.com>
+ *
+ * @copyright Copyright (c) 2018, ownCloud GmbH
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OCA\SystemTags\Tests\unit;
+
+use Test\Traits\UserTrait;
+use OCA\SystemTags\Activity\Listener;
+use OCA\SystemTags\Activity\Extension;
+use OCP\IUserSession;
+use OCP\Activity\IManager;
+use OCP\App\IAppManager;
+use OCP\Files\Config\IMountProviderCollection;
+use OCP\Files\IRootFolder;
+use OCP\Files\Config\IUserMountCache;
+use OCP\Files\Config\ICachedMountInfo;
+use OCP\IUser;
+use OCP\Files\Folder;
+use OCP\Activity\IEvent;
+use OCP\SystemTag\MapperEvent;
+use OCP\IGroupManager;
+use OCP\SystemTag\ISystemTagManager;
+use OCP\SystemTag\ISystemTag;
+use OC\SystemTag\SystemTag;
+
+/**
+ * Tests for the activity listener
+ *
+ * @group DB
+ */
+class ActivityListenerTest extends \Test\TestCase {
+	use UserTrait;
+
+	/**
+	 * @var IGroupManager
+	 */
+	private $groupManager;
+
+	/**
+	 * @var ISystemTagManager
+	 */
+	private $tagManager;
+
+	/**
+	 * @var Listener
+	 */
+	private $listener;
+
+	/**
+	 * @var IUserMountCache
+	 */
+	private $userMountCache;
+
+	/**
+	 * @var IRootFolder
+	 */
+	private $rootFolder;
+
+	/**
+	 * @var IUserSession
+	 */
+	private $userSession;
+
+	/**
+	 * @var IManager
+	 */
+	private $activityManager;
+
+	protected function setUp() {
+		parent::setUp();
+
+		$this->groupManager = $this->createMock(IGroupManager::class);
+
+		$this->tagManager = $this->createMock(ISystemTagManager::class);
+		$this->activityManager = $this->createMock(IManager::class);
+		$this->userSession = $this->createMock(IUserSession::class);
+
+		$appManager = $this->createMock(IAppManager::class);
+		$appManager->method('isInstalled')->with('activity')->willReturn(true);
+
+		$this->userMountCache = $this->createMock(IUserMountCache::class);
+
+		$mountProviderCollection = $this->createMock(IMountProviderCollection::class);
+		$mountProviderCollection->method('getMountCache')->willReturn($this->userMountCache);
+
+		$this->rootFolder = $this->createMock(IRootFolder::class);
+
+		$this->listener = $this->getMockBuilder(Listener::class)
+			->setConstructorArgs([
+				$this->groupManager,
+				$this->activityManager,
+				$this->userSession,
+				$this->tagManager,
+				$appManager,
+				$mountProviderCollection,
+				$this->rootFolder
+			])
+			->setMethods(['getUsersSharingFile'])
+			->getMock();
+	}
+
+	public function providesEventTypes() {
+		return [
+			[MapperEvent::EVENT_ASSIGN, Extension::ASSIGN_TAG],
+			[MapperEvent::EVENT_UNASSIGN, Extension::UNASSIGN_TAG],
+		];
+	}
+
+	/**
+	 * @dataProvider providesEventTypes
+	 */
+	public function testActivityOnMapperEvent($eventType, $extensionEvent) {
+		$user = $this->createMock(IUser::class);
+		$user->method('getUID')->willReturn('user1');
+
+		$actor = $this->createMock(IUser::class);
+		$actor->method('getUID')->willReturn('actor1');
+
+		$this->userSession->method('getUser')->willReturn($actor);
+
+		$tag1 = $this->createMock(ISystemTag::class);
+		$tag1->method('isUserVisible')->willReturn(true);
+		$tag1->method('isUserAssignable')->willReturn(true);
+		$tag1->method('isUserEditable')->willReturn(true);
+		$tag1->method('getName')->willReturn('tag1');
+
+		$tag2 = $this->createMock(ISystemTag::class);
+		$tag2->method('isUserVisible')->willReturn(true);
+		$tag2->method('isUserAssignable')->willReturn(false);
+		$tag2->method('isUserEditable')->willReturn(false);
+		$tag2->method('getName')->willReturn('tag2');
+
+		$invisibleTag = $this->createMock(ISystemTag::class);
+		$invisibleTag->method('isUserVisible')->willReturn(false);
+
+		$this->groupManager->method('isAdmin')->willReturn(false);
+
+		$this->tagManager->method('getTagsByIds')
+			->with([111, 222, 333])
+			->willReturn([$tag1, $tag2, $invisibleTag]);
+
+		$cachedMountInfo = $this->createMock(ICachedMountInfo::class);
+		$cachedMountInfo->method('getUser')->willReturn($user);
+
+		$node = $this->createMock(Folder::class);
+		$node->method('getPath')->willReturn('/user1/files/folder');
+
+		$ownerFolder = $this->createMock(Folder::class);
+		$ownerFolder->method('getById')
+			->with(123, true)
+			->willReturn([$node]);
+
+		$this->rootFolder->method('getUserFolder')
+			->with('user1')
+			->willReturn($ownerFolder);
+
+		$this->userMountCache->method('getMountsForFileId')
+			->with(123)
+			->willReturn([$cachedMountInfo]);
+
+		$this->listener->method('getUsersSharingFile')->willReturn(['user1' => '/folder']);
+
+		$activityEvent = $this->createMock(IEvent::class);
+		$activityEvent->expects($this->once())->method('setApp')->with('systemtags')->willReturn($activityEvent);
+		$activityEvent->expects($this->once())->method('setType')->with('systemtags')->willReturn($activityEvent);
+		$activityEvent->expects($this->once())->method('setAuthor')->with('actor1')->willReturn($activityEvent);
+		$activityEvent->expects($this->once())->method('setObject')->with('files', 123)->willReturn($activityEvent);
+		$activityEvent->expects($this->exactly(2))->method('setSubject')
+			->withConsecutive(
+				[$extensionEvent, ['actor1', '/folder', '{{{tag1|||assignable}}}']],
+				[$extensionEvent, ['actor1', '/folder', '{{{tag2|||not-assignable}}}']]
+			)
+			->willReturn($activityEvent);
+
+		$this->activityManager->method('generateEvent')
+			->willReturn($activityEvent);
+		$this->activityManager->expects($this->exactly(2))
+			->method('publish')
+			->with($activityEvent);
+
+		$event = new MapperEvent($eventType, 'files', 123, [111, 222, 333]);
+		$this->listener->mapperEvent($event);
+	}
+
+	public function prepareTagAsParameterProvider() {
+		return [
+			[new SystemTag('1', 'visibleTag', true, true, true), "{{{visibleTag|||assignable}}}"],
+			[new SystemTag('2', 'invisibleTag', false, false, false), "{{{invisibleTag|||invisible}}}"],
+			[new SystemTag('3', 'restrictTag', true, false, false), "{{{restrictTag|||not-assignable}}}"],
+			[new SystemTag('3', 'staticTag', true, true, false), "{{{staticTag|||not-editable}}}"],
+		];
+	}
+
+	/**
+	 * @dataProvider prepareTagAsParameterProvider
+	 */
+	public function testPrepareTagAsParameter(SystemTag $tag, $expectedResult) {
+		$result = $this->invokePrivate($this->listener, 'prepareTagAsParameter', [$tag]);
+		$this->assertEquals($expectedResult, $result);
+	}
+}
diff --git a/lib/private/Files/Config/CachedMountInfo.php b/lib/private/Files/Config/CachedMountInfo.php
index d2b3c78f393a..cc3074150142 100644
--- a/lib/private/Files/Config/CachedMountInfo.php
+++ b/lib/private/Files/Config/CachedMountInfo.php
@@ -91,12 +91,8 @@ public function getMountPointNode() {
 		// TODO injection etc
 		Filesystem::initMountPoints($this->getUser()->getUID());
 		$userNode = \OC::$server->getUserFolder($this->getUser()->getUID());
-		$nodes = $userNode->getParent()->getById($this->getRootId());
-		if (\count($nodes) > 0) {
-			return $nodes[0];
-		} else {
-			return null;
-		}
+		$nodes = $userNode->getParent()->getById($this->getRootId(), true);
+		return $nodes[0] ?? null;
 	}
 
 	/**
diff --git a/lib/private/Files/Meta/MetaFileIdNode.php b/lib/private/Files/Meta/MetaFileIdNode.php
index b04d344b247e..2f8407ea9fb5 100644
--- a/lib/private/Files/Meta/MetaFileIdNode.php
+++ b/lib/private/Files/Meta/MetaFileIdNode.php
@@ -34,8 +34,8 @@
  */
 class MetaFileIdNode extends AbstractFolder {
 
-	/** @var int */
-	private $fileId;
+	/** @var \OCP\Files\Node */
+	private $node;
 	/** @var MetaRootNode */
 	private $parentNode;
 	/** @var IRootFolder */
@@ -45,12 +45,13 @@ class MetaFileIdNode extends AbstractFolder {
 	 * MetaFileIdNode constructor.
 	 *
 	 * @param MetaRootNode $parentNode
-	 * @param int $fileId
+	 * @param IRootFolder $root
+	 * @param \OCP\Files\Node $node
 	 */
-	public function __construct(MetaRootNode $parentNode, IRootFolder $root, $fileId) {
+	public function __construct(MetaRootNode $parentNode, IRootFolder $root, \OCP\Files\Node $node) {
 		$this->parentNode = $parentNode;
-		$this->fileId = $fileId;
 		$this->root = $root;
+		$this->node = $node;
 	}
 
 	/**
@@ -79,7 +80,7 @@ public function isMounted() {
 	 */
 	public function getDirectoryListing() {
 		return [
-			new MetaVersionCollection($this->fileId, $this->root)
+			new MetaVersionCollection($this->root, $this->node)
 		];
 	}
 
@@ -90,7 +91,7 @@ public function get($path) {
 		$pieces = \explode('/', $path);
 		if ($pieces[0] === 'v') {
 			\array_shift($pieces);
-			$node = new MetaVersionCollection($this->fileId, $this->root);
+			$node = new MetaVersionCollection($this->root, $this->node);
 			if (empty($pieces)) {
 				return $node;
 			}
@@ -117,7 +118,7 @@ public function getPath() {
 	 * @inheritdoc
 	 */
 	public function getInternalPath() {
-		return "/meta/{$this->fileId}";
+		return "/meta/{$this->node->getId()}";
 	}
 
 	/**
@@ -166,6 +167,6 @@ public function getParent() {
 	 * @inheritdoc
 	 */
 	public function getName() {
-		return "{$this->fileId}";
+		return "{$this->node->getId()}";
 	}
 }
diff --git a/lib/private/Files/Meta/MetaRootNode.php b/lib/private/Files/Meta/MetaRootNode.php
index 6a893652c115..930180f5d714 100644
--- a/lib/private/Files/Meta/MetaRootNode.php
+++ b/lib/private/Files/Meta/MetaRootNode.php
@@ -76,13 +76,13 @@ public function get($path) {
 		$pieces = \explode('/', $path);
 		$fileId = (int)$pieces[0];
 
-		// check if file exists
-		if (empty($this->rootFolder->getById($fileId))) {
+		$nodes = $this->rootFolder->getById($fileId, true);
+		if (empty($nodes)) {
 			throw new NotFoundException();
 		}
 
 		\array_shift($pieces);
-		$node = new MetaFileIdNode($this, $this->rootFolder, $fileId);
+		$node = new MetaFileIdNode($this, $this->rootFolder, $nodes[0]);
 		if (empty($pieces)) {
 			return $node;
 		}
@@ -92,7 +92,7 @@ public function get($path) {
 	/**
 	 * @inheritdoc
 	 */
-	public function getById($id) {
+	public function getById($id, $first = false) {
 		return [
 			$this->get("$id")
 			];
diff --git a/lib/private/Files/Meta/MetaVersionCollection.php b/lib/private/Files/Meta/MetaVersionCollection.php
index 5e63c7d0f43e..fd3a238efa64 100644
--- a/lib/private/Files/Meta/MetaVersionCollection.php
+++ b/lib/private/Files/Meta/MetaVersionCollection.php
@@ -1,5 +1,6 @@
 <?php
 /**
+ * @author Jörn Friedrich Dreyer <jfd@butonic.de>
  * @author Thomas Müller <thomas.mueller@tmit.eu>
  *
  * @copyright Copyright (c) 2018, ownCloud GmbH
@@ -24,7 +25,6 @@
 use OC\Files\Node\AbstractFolder;
 use OCP\Files\IRootFolder;
 use OCP\Files\Storage\IVersionedStorage;
-use OC\Files\View;
 use OCP\Files\NotFoundException;
 use OCP\Files\Storage;
 
@@ -36,20 +36,20 @@
  */
 class MetaVersionCollection extends AbstractFolder {
 
-	/** @var int */
-	private $fileId;
 	/** @var IRootFolder */
 	private $root;
+	/** @var \OCP\Files\Node */
+	private $node;
 
 	/**
 	 * MetaVersionCollection constructor.
 	 *
-	 * @param int $fileId
 	 * @param IRootFolder $root
+	 * @param \OCP\Files\Node $node
 	 */
-	public function __construct($fileId, IRootFolder $root) {
-		$this->fileId = $fileId;
+	public function __construct(IRootFolder $root, \OCP\Files\Node $node) {
 		$this->root = $root;
+		$this->node = $node;
 	}
 
 	/**
@@ -66,22 +66,19 @@ public function isShared() {
 		return false;
 	}
 
-	/**
-	 * @inheritdoc
-	 */
 	public function getDirectoryListing() {
-		$view = new View();
-		$path = $view->getPath($this->fileId, false);
-		/** @var Storage $storage */
-		list($storage, $internalPath) = $view->resolvePath($path);
+		$node = $this->node;
+		$storage = $node->getStorage();
+		$internalPath = $node->getInternalPath();
+
 		if (!$storage->instanceOfStorage(IVersionedStorage::class)) {
 			return [];
 		}
 		/** @var IVersionedStorage | Storage $storage */
 		$versions = $storage->getVersions($internalPath);
-		return \array_values(\array_map(function ($version) use ($storage, $internalPath, $view, $path) {
+		return \array_values(\array_map(function ($version) use ($storage, $node, $internalPath) {
 			if (!isset($version['mimetype'])) {
-				$version['mimetype'] = $view->getMimeType($path);
+				$version['mimetype'] = $node->getMimetype();
 			}
 
 			return new MetaFileVersionNode($this, $this->root, $version, $storage, $internalPath);
@@ -97,10 +94,10 @@ public function get($path) {
 			throw new NotFoundException();
 		}
 		$versionId = $pieces[0];
-		$view = new View();
-		$path = $view->getPath($this->fileId);
-		/** @var Storage $storage */
-		list($storage, $internalPath) = $view->resolvePath($path);
+
+		$storage = $this->node->getStorage();
+		$internalPath = $this->node->getInternalPath();
+
 		if (!$storage->instanceOfStorage(IVersionedStorage::class)) {
 			throw new NotFoundException();
 		}
@@ -110,7 +107,7 @@ public function get($path) {
 			throw new NotFoundException();
 		}
 		if (!isset($version['mimetype'])) {
-			$version['mimetype'] = $view->getMimeType($path);
+			$version['mimetype'] = $this->node->getMimetype();
 		}
 		return new MetaFileVersionNode($this, $this->root, $version, $storage, $internalPath);
 	}
@@ -119,7 +116,7 @@ public function get($path) {
 	 * @inheritdoc
 	 */
 	public function getId() {
-		return $this->fileId;
+		return $this->node->getId();
 	}
 
 	public function getName() {
@@ -127,6 +124,6 @@ public function getName() {
 	}
 
 	public function getPath() {
-		return "/meta/{$this->fileId}/v";
+		return "/meta/{$this->getId()}/v";
 	}
 }
diff --git a/lib/private/Files/Node/AbstractFolder.php b/lib/private/Files/Node/AbstractFolder.php
index fb6c3feea3a4..d652c026a2f6 100644
--- a/lib/private/Files/Node/AbstractFolder.php
+++ b/lib/private/Files/Node/AbstractFolder.php
@@ -112,7 +112,7 @@ public function searchByTag($tag, $userId) {
 	/**
 	 * @inheritdoc
 	 */
-	public function getById($id) {
+	public function getById($id, $first = false) {
 		throw new NotPermittedException();
 	}
 
diff --git a/lib/private/Files/Node/Folder.php b/lib/private/Files/Node/Folder.php
index adb9e56a1b4c..ca559a1f7e86 100644
--- a/lib/private/Files/Node/Folder.php
+++ b/lib/private/Files/Node/Folder.php
@@ -269,9 +269,11 @@ private function searchCommon($method, $args) {
 
 	/**
 	 * @param int $id
+	 * @param boolean $first only return the first node that is found
 	 * @return \OC\Files\Node\Node[]
+	 * @throws NotFoundException
 	 */
-	public function getById($id) {
+	public function getById($id, $first = false) {
 		$mounts = $this->root->getMountsIn($this->path);
 		$mounts[] = $this->root->getMount($this->path);
 		// reverse the array so we start with the storage this view is in
@@ -290,6 +292,9 @@ public function getById($id) {
 					$fullPath = $mount->getMountPoint() . $internalPath;
 					if (($path = $this->getRelativePath($fullPath)) !== null) {
 						$nodes[] = $this->get($path);
+						if ($first) {
+							break;
+						}
 					}
 				}
 			}
diff --git a/lib/private/Files/Node/LazyRoot.php b/lib/private/Files/Node/LazyRoot.php
index 9e43f7e09b47..c9bf01f71525 100644
--- a/lib/private/Files/Node/LazyRoot.php
+++ b/lib/private/Files/Node/LazyRoot.php
@@ -417,7 +417,7 @@ public function searchByTag($tag, $userId) {
 	/**
 	 * @inheritDoc
 	 */
-	public function getById($id) {
+	public function getById($id, $first = false) {
 		return $this->__call(__FUNCTION__, \func_get_args());
 	}
 
diff --git a/lib/private/Files/Node/NonExistingFolder.php b/lib/private/Files/Node/NonExistingFolder.php
index c3634403fea6..032e5764312c 100644
--- a/lib/private/Files/Node/NonExistingFolder.php
+++ b/lib/private/Files/Node/NonExistingFolder.php
@@ -154,7 +154,7 @@ public function searchByTag($tag, $userId) {
 		throw new NotFoundException();
 	}
 
-	public function getById($id) {
+	public function getById($id, $first = false) {
 		throw new NotFoundException();
 	}
 
diff --git a/lib/private/Files/Storage/Wrapper/Jail.php b/lib/private/Files/Storage/Wrapper/Jail.php
index f533cd8330f1..24d12774d8a0 100644
--- a/lib/private/Files/Storage/Wrapper/Jail.php
+++ b/lib/private/Files/Storage/Wrapper/Jail.php
@@ -26,6 +26,7 @@
 
 use OC\Files\Cache\Wrapper\CacheJail;
 use OCP\Files\Storage\IStorage;
+use OCP\Files\Storage\IVersionedStorage;
 use OCP\Lock\ILockingProvider;
 
 /**
@@ -33,7 +34,8 @@
  *
  * This restricts access to a subfolder of the wrapped storage with the subfolder becoming the root folder new storage
  */
-class Jail extends Wrapper {
+class Jail extends Wrapper /* implements IVersionedStorage */
+{
 	/**
 	 * @var string
 	 */
@@ -497,4 +499,62 @@ public function moveFromStorage(\OCP\Files\Storage $sourceStorage, $sourceIntern
 		}
 		return $this->getWrapperStorage()->moveFromStorage($sourceStorage, $sourceInternalPath, $this->getSourcePath($targetInternalPath));
 	}
+
+	/**
+	 * Get the content of a given version of a given file as stream resource
+	 *
+	 * @param string $internalPath
+	 * @param string $versionId
+	 * @return resource
+	 * @since 10.0.9
+	 */
+	public function getContentOfVersion($internalPath, $versionId) {
+		return $this->getWrapperStorage()->getContentOfVersion($this->getSourcePath($internalPath), $versionId);
+	}
+
+	/**
+	 * Restore the given version of a given file
+	 *
+	 * @param string $internalPath
+	 * @param string $versionId
+	 * @return boolean
+	 * @since 10.0.9
+	 */
+	public function restoreVersion($internalPath, $versionId) {
+		return $this->getWrapperStorage()->restoreVersion($this->getSourcePath($internalPath), $versionId);
+	}
+
+	/**
+	 * Tells the storage to explicitly create a version of a given file
+	 *
+	 * @param string $internalPath
+	 * @return bool
+	 * @since 10.0.9
+	 */
+	public function saveVersion($internalPath) {
+		return $this->getWrapperStorage()->saveVersion($this->getSourcePath($internalPath));
+	}
+
+	/**
+	 * List all versions for the given file
+	 *
+	 * @param string $internalPath
+	 * @return array
+	 * @since 10.0.9
+	 */
+	public function getVersions($internalPath) {
+		return $this->getWrapperStorage()->getVersions($this->getSourcePath($internalPath));
+	}
+
+	/**
+	 * Get one explicit version for the given file
+	 *
+	 * @param string $internalPath
+	 * @param string $versionId
+	 * @return array
+	 * @since 10.0.9
+	 */
+	public function getVersion($internalPath, $versionId) {
+		return $this->getWrapperStorage()->getVersion($this->getSourcePath($internalPath), $versionId);
+	}
 }
diff --git a/lib/private/Share20/Share.php b/lib/private/Share20/Share.php
index 6f774f08f653..4fa7e4ccfe93 100644
--- a/lib/private/Share20/Share.php
+++ b/lib/private/Share20/Share.php
@@ -164,7 +164,7 @@ public function getNode() {
 				$userFolder = $this->rootFolder->getUserFolder($this->sharedBy);
 			}
 
-			$nodes = $userFolder->getById($this->fileId);
+			$nodes = $userFolder->getById($this->fileId, true);
 			if (empty($nodes)) {
 				throw new NotFoundException();
 			}
diff --git a/lib/public/Files/Folder.php b/lib/public/Files/Folder.php
index 2dfa83a409ed..55f5211bc22d 100644
--- a/lib/public/Files/Folder.php
+++ b/lib/public/Files/Folder.php
@@ -145,10 +145,11 @@ public function searchByTag($tag, $userId);
 	 * get a file or folder inside the folder by it's internal id
 	 *
 	 * @param int $id
+	 * @param boolean $first only return the first node that is found
 	 * @return \OCP\Files\Node[]
 	 * @since 6.0.0
 	 */
-	public function getById($id);
+	public function getById($id, $first = false);
 
 	/**
 	 * Get the amount of free space inside the folder
diff --git a/tests/lib/Files/MetaFilesTest.php b/tests/lib/Files/MetaFilesTest.php
index 28bac72710ff..9db1638234dd 100644
--- a/tests/lib/Files/MetaFilesTest.php
+++ b/tests/lib/Files/MetaFilesTest.php
@@ -43,11 +43,36 @@
 class MetaFilesTest extends TestCase {
 	use UserTrait;
 
+	/**
+	 * @var string
+	 */
+	private $userId;
+
+	protected function setUp() {
+		parent::setUp();
+
+		// workaround: re-setup versions hooks
+		Hooks::connectHooks();
+
+		$this->userId = $this->getUniqueID('meta-data-user-');
+		$this->createUser($this->userId);
+		$this->loginAsUser($this->userId);
+	}
+
 	protected function tearDown() {
 		self::logout();
 		parent::tearDown();
 	}
 
+	private function createFile() {
+		// create file
+		$file = $this->getUniqueID('file') . '.txt';
+		$fileName = "{$this->userId}/files/$file";
+		$view = new View();
+		$view->file_put_contents($fileName, '1234');
+		return $view->getFileInfo($fileName);
+	}
+
 	/**
 	 * @throws \Exception
 	 * @throws \OCP\Files\ForbiddenException
@@ -55,17 +80,11 @@ protected function tearDown() {
 	 * @throws \OCP\Files\NotPermittedException
 	 */
 	public function testMetaInNodeAPI() {
-		// workaround: re-setup versions hooks
-		Hooks::connectHooks();
-
-		// create user
-		$userId = 'meta-data-user';
-		$this->createUser($userId);
-		$this->loginAsUser($userId);
+		$userId = $this->userId;
 
 		// create file
 		$file = $this->getUniqueID('file') . '.txt';
-		$fileName = "$userId/files/$file";
+		$fileName = "{$this->userId}/files/$file";
 		$view = new View();
 		$view->file_put_contents($fileName, '1234');
 		$info = $view->getFileInfo($fileName);
@@ -124,4 +143,25 @@ public function testMetaInNodeAPI() {
 		$metaNodeOfFile->copy($fileName);
 		$this->assertEquals('1234', $target->getContent());
 	}
+
+	public function testMetaRootGetById() {
+		$info = $this->createFile();
+
+		$metaRoot = \OC::$server->getRootFolder();
+		$info2 = $metaRoot->getById($info->getId());
+
+		$this->assertEquals($info->getId(), $info2[0]->getId());
+		$this->assertEquals($info->getPath(), $info2[0]->getPath());
+	}
+
+	/**
+	 * @expectedException OCP\Files\NotFoundException
+	 */
+	public function testMetaRootGetNotFound() {
+		$info = $this->createFile();
+
+		$metaRoot = \OC::$server->getRootFolder();
+		// get non-existing
+		$metaRoot->get($info->getId() + 100);
+	}
 }
diff --git a/tests/lib/Files/MetaVersionCollectionTest.php b/tests/lib/Files/MetaVersionCollectionTest.php
new file mode 100644
index 000000000000..0659d6057361
--- /dev/null
+++ b/tests/lib/Files/MetaVersionCollectionTest.php
@@ -0,0 +1,166 @@
+<?php
+/**
+ * @author Vincent Petry <pvince81@owncloud.com>
+ *
+ * @copyright Copyright (c) 2018, ownCloud GmbH
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace Test\Files;
+
+use Test\TestCase;
+use OCP\Files\Node;
+use OC\Files\Meta\MetaVersionCollection;
+use OCP\Files\IRootFolder;
+use OCP\Files\Storage\IStorage;
+use OCA\Files_Sharing\External\Storage;
+use OCP\Files\Storage\IVersionedStorage;
+use OC\Files\Meta\MetaFileVersionNode;
+
+/**
+ * Class MetaFilesTest
+ *
+ * @package Test\Files
+ */
+class MetaVersionCollectionTest extends TestCase {
+
+	/**
+	 * @var Node
+	 */
+	private $node;
+
+	/**
+	 * @var IRootFolder
+	 */
+	private $rootFolder;
+
+	/**
+	 * @var MetaVersionCollection
+	 */
+	private $collection;
+
+	/**
+	 * @var IStorage|IVersionedStorage
+	 */
+	private $storage;
+
+	protected function setUp() {
+		parent::setUp();
+
+		$this->rootFolder = $this->createMock(IRootFolder::class);
+		$this->node = $this->createMock(Node::class);
+		$this->storage = $this->createMock([IStorage::class, IVersionedStorage::class]);
+		$this->node->method('getStorage')->willReturn($this->storage);
+		$this->collection = new MetaVersionCollection($this->rootFolder, $this->node);
+	}
+
+	protected function tearDown() {
+		parent::tearDown();
+	}
+
+	public function testGetDirectoryListing() {
+		$this->node->method('getInternalPath')->willReturn('/abc');
+		$this->node->method('getMimetype')->willReturn('application/json');
+
+		$this->storage->method('instanceOfStorage')
+			->with(IVersionedStorage::class)
+			->willReturn(true);
+
+		$this->storage->expects($this->once())
+			->method('getVersions')
+			->with('/abc')
+			->willReturn([
+				['version' => '1014', 'timestamp' => 12345678],
+				['version' => '1015', 'mimetype' => 'text/plain', 'timestamp' => 12345679],
+			]);
+
+		$children = $this->collection->getDirectoryListing();
+
+		$this->assertCount(2, $children);
+		$this->assertInstanceOf(MetaFileVersionNode::class, $children[0]);
+		$this->assertEquals('1014', $children[0]->getName());
+		$this->assertEquals('application/json', $children[0]->getMimetype());
+		$this->assertEquals(12345678, $children[0]->getMtime());
+		$this->assertInstanceOf(MetaFileVersionNode::class, $children[1]);
+		$this->assertEquals('1015', $children[1]->getName());
+		$this->assertEquals('text/plain', $children[1]->getMimetype());
+		$this->assertEquals(12345679, $children[1]->getMtime());
+	}
+
+	public function testGetDirectoryListingNonVersionedStorage() {
+		$this->node->method('getInternalPath')->willReturn('/abc');
+		$this->node->method('getMimetype')->willReturn('application/json');
+
+		$this->storage->method('instanceOfStorage')
+			->with(IVersionedStorage::class)
+			->willReturn(false);
+
+		$this->storage->expects($this->never())
+			->method('getVersions');
+
+		$children = $this->collection->getDirectoryListing();
+
+		$this->assertCount(0, $children);
+	}
+
+	public function testGet() {
+		$this->node->method('getInternalPath')->willReturn('/abc');
+		$this->node->method('getMimetype')->willReturn('application/json');
+
+		$this->storage->method('instanceOfStorage')
+			->with(IVersionedStorage::class)
+			->willReturn(true);
+
+		$this->storage->expects($this->once())
+			->method('getVersion')
+			->with('/abc', '1014')
+			->willReturn(['version' => '1014', 'timestamp' => 12345678]);
+
+		$result = $this->collection->get('1014');
+
+		$this->assertInstanceOf(MetaFileVersionNode::class, $result);
+		$this->assertEquals('1014', $result->getName());
+		$this->assertEquals('application/json', $result->getMimetype());
+		$this->assertEquals(12345678, $result->getMtime());
+	}
+
+	/**
+	 * @expectedException OCP\Files\NotFoundException
+	 */
+	public function testGetNonVersionedStorageFails() {
+		$this->node->method('getInternalPath')->willReturn('/abc');
+		$this->node->method('getMimetype')->willReturn('application/json');
+
+		$this->storage->method('instanceOfStorage')
+			->with(IVersionedStorage::class)
+			->willReturn(false);
+
+		$this->storage->expects($this->never())
+			->method('getVersion');
+
+		$this->collection->get('1014');
+	}
+
+	/**
+	 * @expectedException OCP\Files\NotFoundException
+	 */
+	public function testGetSubEntryFails() {
+		$this->storage->expects($this->never())
+			->method('instanceOfStorage');
+
+		$this->collection->get('1014/1');
+	}
+}
diff --git a/tests/lib/Files/Storage/Wrapper/JailTest.php b/tests/lib/Files/Storage/Wrapper/JailTest.php
index 122953e9e54d..1b8f708155a5 100644
--- a/tests/lib/Files/Storage/Wrapper/JailTest.php
+++ b/tests/lib/Files/Storage/Wrapper/JailTest.php
@@ -8,6 +8,9 @@
 
 namespace Test\Files\Storage\Wrapper;
 
+use OCP\Files\Storage\IStorage;
+use OCP\Files\Storage\IVersionedStorage;
+
 class JailTest extends \Test\Files\Storage\Storage {
 
 	/**
@@ -48,4 +51,37 @@ public function testFilePutContentsRooted() {
 		$this->instance->file_put_contents('bar', 'asd');
 		$this->assertEquals('asd', $this->sourceStorage->file_get_contents('foo/bar'));
 	}
+
+	public function providesVersionMethods() {
+		return [
+			['getContentOfVersion', 1014],
+			['restoreVersion', 1014],
+			['saveVersion'],
+			['getVersions'],
+			['getVersion', 1014],
+		];
+	}
+
+	/**
+	 * @dataProvider providesVersionMethods
+	 */
+	public function testCallsSourceVersionMethods($method, $extraArg = null) {
+		$sourceStorage = $this->createMock([IStorage::class, IVersionedStorage::class]);
+		$instance = new \OC\Files\Storage\Wrapper\Jail([
+			'storage' => $sourceStorage,
+			'root' => 'foo'
+		]);
+
+		$matcher = $sourceStorage->expects($this->once())
+			->method($method);
+		// FIXME: normalize path...
+		if ($extraArg !== null) {
+			$matcher = $matcher->with('foo//bar', $extraArg);
+		} else {
+			$matcher = $matcher->with('foo//bar');
+		}
+		$matcher->willReturn('returnValue');
+
+		$this->assertEquals('returnValue', $instance->$method('/bar', $extraArg));
+	}
 }