diff --git a/apps/files_encryption/hooks/hooks.php b/apps/files_encryption/hooks/hooks.php
index 8bfd0a7845f..0d050e12a95 100644
--- a/apps/files_encryption/hooks/hooks.php
+++ b/apps/files_encryption/hooks/hooks.php
@@ -101,11 +101,9 @@ class Hooks {
 				$userView->file_exists('encryption.key')
 				&& $encLegacyKey = $userView->file_get_contents('encryption.key')
 			) {
+					$plainLegacyKey = Crypt::legacyDecrypt($encLegacyKey, $params['password']);
 
-				$plainLegacyKey = Crypt::legacyDecrypt($encLegacyKey, $params['password']);
-
-				$session->setLegacyKey($plainLegacyKey);
-
+					$session->setLegacyKey($plainLegacyKey);
 			}
 
 			// Encrypt existing user files
diff --git a/apps/files_encryption/lib/proxy.php b/apps/files_encryption/lib/proxy.php
index ef40c18183f..70278234b7c 100644
--- a/apps/files_encryption/lib/proxy.php
+++ b/apps/files_encryption/lib/proxy.php
@@ -311,7 +311,7 @@ class Proxy extends \OC_FileProxy {
 			\OC_FileProxy::$enabled = false;
 
 			// get file size
-			$data['size'] = self::postFileSize($path, $data['size']);
+			$data['size'] = self::postFileSize($path, $data['size'], $data);
 
 			// Re-enable the proxy
 			\OC_FileProxy::$enabled = $proxyStatus;
@@ -325,7 +325,7 @@ class Proxy extends \OC_FileProxy {
 	 * @param $size
 	 * @return bool
 	 */
-	public function postFileSize($path, $size) {
+	public function postFileSize($path, $size, $fileInfo = null) {
 
 		$view = new \OC_FilesystemView('/');
 
@@ -359,9 +359,8 @@ class Proxy extends \OC_FileProxy {
 			return $size;
 		}
 
-		$fileInfo = false;
 		// get file info from database/cache if not .part file
-		if (!Helper::isPartialFilePath($path)) {
+		if (empty($fileInfo) && !Helper::isPartialFilePath($path)) {
 			$proxyState = \OC_FileProxy::$enabled;
 			\OC_FileProxy::$enabled = false;
 			$fileInfo = $view->getFileInfo($path);
@@ -369,7 +368,7 @@ class Proxy extends \OC_FileProxy {
 		}
 
 		// if file is encrypted return real file size
-		if (is_array($fileInfo) && $fileInfo['encrypted'] === true) {
+		if (isset($fileInfo['encrypted']) && $fileInfo['encrypted'] === true) {
 			// try to fix unencrypted file size if it doesn't look plausible
 			if ((int)$fileInfo['size'] > 0 && (int)$fileInfo['unencrypted_size'] === 0 ) {
 				$fixSize = $util->getFileSize($path);
diff --git a/apps/files_encryption/tests/stream.php b/apps/files_encryption/tests/stream.php
index d26cd75648b..8b9dc38a761 100644
--- a/apps/files_encryption/tests/stream.php
+++ b/apps/files_encryption/tests/stream.php
@@ -136,6 +136,8 @@ class Test_Encryption_Stream extends \PHPUnit_Framework_TestCase {
 		// set stream options
 		$this->assertTrue(stream_set_blocking($handle, 1));
 
+		fclose($handle);
+
 		// tear down
 		$view->unlink($filename);
 	}
@@ -158,6 +160,8 @@ class Test_Encryption_Stream extends \PHPUnit_Framework_TestCase {
 		// set stream options
 		$this->assertFalse(stream_set_timeout($handle, 1));
 
+		fclose($handle);
+
 		// tear down
 		$view->unlink($filename);
 	}
@@ -177,6 +181,8 @@ class Test_Encryption_Stream extends \PHPUnit_Framework_TestCase {
 		// set stream options
 		$this->assertEquals(0, stream_set_write_buffer($handle, 1024));
 
+		fclose($handle);
+
 		// tear down
 		$view->unlink($filename);
 	}
diff --git a/apps/files_encryption/tests/webdav.php b/apps/files_encryption/tests/webdav.php
index 8e8b9c53cee..7f728970675 100755
--- a/apps/files_encryption/tests/webdav.php
+++ b/apps/files_encryption/tests/webdav.php
@@ -48,6 +48,8 @@ class Test_Encryption_Webdav extends \PHPUnit_Framework_TestCase {
 	public $dataShort;
 	public $stateFilesTrashbin;
 
+	private $storage;
+
 	public static function setUpBeforeClass() {
 		// reset backend
 		\OC_User::clearBackends();
@@ -77,8 +79,8 @@ class Test_Encryption_Webdav extends \PHPUnit_Framework_TestCase {
 		$this->pass = \Test_Encryption_Webdav::TEST_ENCRYPTION_WEBDAV_USER1;
 
 		// init filesystem view
-		$this->view = new \OC_FilesystemView('/');
-
+		$this->view = new \OC\Files\View('/');
+		list($this->storage, $intPath) = $this->view->resolvePath('/');
 		// init short data
 		$this->dataShort = 'hats';
 
@@ -196,6 +198,9 @@ class Test_Encryption_Webdav extends \PHPUnit_Framework_TestCase {
 		$_SERVER['HTTP_AUTHORIZATION'] = 'Basic dGVzdC13ZWJkYXYtdXNlcjE6dGVzdC13ZWJkYXYtdXNlcjE=';
 		$_SERVER['PATH_INFO'] = '/webdav' . $filename;
 
+		// at the beginning the file should exist
+		$this->assertTrue($this->view->file_exists('/' . $this->userId . '/files' . $filename));
+
 		// handle webdav request
 		$content = $this->handleWebdavRequest();
 
diff --git a/lib/private/connector/sabre/exception/filelocked.php b/lib/private/connector/sabre/exception/filelocked.php
new file mode 100644
index 00000000000..ec200f847e3
--- /dev/null
+++ b/lib/private/connector/sabre/exception/filelocked.php
@@ -0,0 +1,28 @@
+<?php
+/**
+ * ownCloud
+ *
+ * @author Owen Winkler
+ * @copyright 2013 Owen Winkler <owen@owncloud.com>
+ *
+ */
+
+class OC_Connector_Sabre_Exception_FileLocked extends Sabre_DAV_Exception {
+
+	public function __construct($message = "", $code = 0, Exception $previous = null) {
+		if($previous instanceof \OCP\Files\LockNotAcquiredException) {
+			$message = sprintf('Target file %s is locked by another process.', $previous->path);
+		}
+		parent::__construct($message, $code, $previous);
+	}
+
+	/**
+	 * Returns the HTTP status code for this exception
+	 *
+	 * @return int
+	 */
+	public function getHTTPCode() {
+
+		return 503;
+	}
+}
diff --git a/lib/private/connector/sabre/file.php b/lib/private/connector/sabre/file.php
index d61d97938c7..bc528cde794 100644
--- a/lib/private/connector/sabre/file.php
+++ b/lib/private/connector/sabre/file.php
@@ -97,15 +97,24 @@ class OC_Connector_Sabre_File extends OC_Connector_Sabre_Node implements Sabre_D
 			// the path for the file was not valid
 			// TODO: find proper http status code for this case
 			throw new Sabre_DAV_Exception_Forbidden($e->getMessage());
+		} catch (\OCP\Files\LockNotAcquiredException $e) {
+			// the file is currently being written to by another process
+			throw new OC_Connector_Sabre_Exception_FileLocked($e->getMessage(), $e->getCode(), $e);
 		}
 
 		// rename to correct path
-		$renameOkay = $fs->rename($partpath, $this->path);
-		$fileExists = $fs->file_exists($this->path);
-		if ($renameOkay === false || $fileExists === false) {
-			\OC_Log::write('webdav', '\OC\Files\Filesystem::rename() failed', \OC_Log::ERROR);
-			$fs->unlink($partpath);
-			throw new Sabre_DAV_Exception('Could not rename part file to final file');
+		try {
+			$renameOkay = $fs->rename($partpath, $this->path);
+			$fileExists = $fs->file_exists($this->path);
+			if ($renameOkay === false || $fileExists === false) {
+				\OC_Log::write('webdav', '\OC\Files\Filesystem::rename() failed', \OC_Log::ERROR);
+				$fs->unlink($partpath);
+				throw new Sabre_DAV_Exception('Could not rename part file to final file');
+			}
+		}
+		catch (\OCP\Files\LockNotAcquiredException $e) {
+			// the file is currently being written to by another process
+			throw new OC_Connector_Sabre_Exception_FileLocked($e->getMessage(), $e->getCode(), $e);
 		}
 
 		// allow sync clients to send the mtime along in a header
diff --git a/lib/private/files/filesystem.php b/lib/private/files/filesystem.php
index bbced79524f..0aa5f16ec6d 100644
--- a/lib/private/files/filesystem.php
+++ b/lib/private/files/filesystem.php
@@ -152,8 +152,8 @@ class Filesystem {
 	/**
 	 * @param callable $wrapper
 	 */
-	public static function addStorageWrapper($wrapper) {
-		self::getLoader()->addStorageWrapper($wrapper);
+	public static function addStorageWrapper($wrapperName, $wrapper) {
+		self::getLoader()->addStorageWrapper($wrapperName, $wrapper);
 
 		$mounts = self::getMountManager()->getAll();
 		foreach ($mounts as $mount) {
diff --git a/lib/private/files/storage/common.php b/lib/private/files/storage/common.php
index dd5cc915dcb..322c2eb9c0d 100644
--- a/lib/private/files/storage/common.php
+++ b/lib/private/files/storage/common.php
@@ -371,6 +371,15 @@ abstract class Common implements \OC\Files\Storage\Storage {
 	}
 
 	/**
+	 * {@inheritdoc}
+	 */
+	public function isLocal() {
+		// the common implementation returns a temporary file by
+		// default, which is not local
+		return false;
+	}
+
+	/*
 	 * Check if the storage is an instance of $class or is a wrapper for a storage that is an instance of $class
 	 *
 	 * @param string $class
diff --git a/lib/private/files/storage/loader.php b/lib/private/files/storage/loader.php
index 2572ef443bc..0969596bd8c 100644
--- a/lib/private/files/storage/loader.php
+++ b/lib/private/files/storage/loader.php
@@ -21,8 +21,8 @@ class Loader {
 	 *
 	 * @param callable $callback
 	 */
-	public function addStorageWrapper($callback) {
-		$this->storageWrappers[] = $callback;
+	public function addStorageWrapper($wrapperName, $callback) {
+		$this->storageWrappers[$wrapperName] = $callback;
 	}
 
 	public function load($mountPoint, $class, $arguments) {
diff --git a/lib/private/files/storage/local.php b/lib/private/files/storage/local.php
index db3c6bfca3a..d698922b4ac 100644
--- a/lib/private/files/storage/local.php
+++ b/lib/private/files/storage/local.php
@@ -296,7 +296,19 @@ if (\OC_Util::runningOnWindows()) {
 		 * @return bool
 		 */
 		public function hasUpdated($path, $time) {
-			return $this->filemtime($path) > $time;
+			if ($this->file_exists($path)) {
+				return $this->filemtime($path) > $time;
+			} else {
+				return true;
+			}
 		}
+
+		/**
+		 * {@inheritdoc}
+		 */
+		public function isLocal() {
+			return true;
+		}
+
 	}
 }
diff --git a/lib/private/files/storage/wrapper/wrapper.php b/lib/private/files/storage/wrapper/wrapper.php
index c731669b1a5..6b2be92143e 100644
--- a/lib/private/files/storage/wrapper/wrapper.php
+++ b/lib/private/files/storage/wrapper/wrapper.php
@@ -434,6 +434,14 @@ class Wrapper implements \OC\Files\Storage\Storage {
 	}
 
 	/**
+	 * Returns the wrapped storage's value for isLocal()
+	 * @return bool wrapped storage's isLocal() value
+	 */
+	public function isLocal() {
+		return $this->storage->isLocal();
+	}
+
+	/*
 	 * Check if the storage is an instance of $class or is a wrapper for a storage that is an instance of $class
 	 *
 	 * @param string $class
diff --git a/lib/private/helper.php b/lib/private/helper.php
index f56a2cf6840..cca9d29b4b1 100644
--- a/lib/private/helper.php
+++ b/lib/private/helper.php
@@ -903,6 +903,7 @@ class OC_Helper {
 		if ($used < 0) {
 			$used = 0;
 		}
+
 		$free = \OC\Files\Filesystem::free_space($path);
 		if ($free >= 0) {
 			$total = $free + $used;
diff --git a/lib/private/log/owncloud.php b/lib/private/log/owncloud.php
index 3590bbd436d..08d0b7d5f93 100644
--- a/lib/private/log/owncloud.php
+++ b/lib/private/log/owncloud.php
@@ -28,6 +28,7 @@
 
 class OC_Log_Owncloud {
 	static protected $logFile;
+	static protected $reqId;
 
 	/**
 	 * Init class data
@@ -68,8 +69,20 @@ class OC_Log_Owncloud {
 				$timezone = new DateTimeZone('UTC');
 			}
 			$time = new DateTime(null, $timezone);
-			// remove username/passswords from URLs before writing the to the log file
-			$entry=array('app'=>$app, 'message'=>$message, 'level'=>$level, 'time'=> $time->format($format));
+			// remove username/passwords from URLs before writing the to the log file
+			$time = $time->format($format);
+			if($minLevel == OC_Log::DEBUG) {
+				if(empty(self::$reqId)) {
+					self::$reqId = uniqid();
+				}
+				$reqId = self::$reqId;
+				$url = isset($_SERVER['REQUEST_URI']) ? $_SERVER['REQUEST_URI'] : '--';
+				$method = isset($_SERVER['REQUEST_METHOD']) ? $_SERVER['REQUEST_METHOD'] : '--';
+				$entry = compact('reqId', 'app', 'message', 'level', 'time', 'method', 'url');
+			}
+			else {
+				$entry = compact('app', 'message', 'level', 'time');
+			}
 			$entry = json_encode($entry);
 			$handle = @fopen(self::$logFile, 'a');
 			@chmod(self::$logFile, 0640);
diff --git a/lib/private/util.php b/lib/private/util.php
index a88665420fd..5700e98ff3f 100755
--- a/lib/private/util.php
+++ b/lib/private/util.php
@@ -57,7 +57,7 @@ class OC_Util {
 
 		//if we aren't logged in, there is no use to set up the filesystem
 		if( $user != "" ) {
-			\OC\Files\Filesystem::addStorageWrapper(function($mountPoint, $storage){
+			\OC\Files\Filesystem::addStorageWrapper('oc_quota', function($mountPoint, $storage){
 				// set up quota for home storages, even for other users
 				// which can happen when using sharing
 
diff --git a/lib/public/files/locknotacquiredexception.php b/lib/public/files/locknotacquiredexception.php
new file mode 100644
index 00000000000..9fb70e7cbe2
--- /dev/null
+++ b/lib/public/files/locknotacquiredexception.php
@@ -0,0 +1,47 @@
+<?php
+/**
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or any later version.
+ *
+ * This library 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 along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+/**
+ * Public interface of ownCloud for apps to use.
+ * Files/LockNotAcquiredException class
+ */
+
+// use OCP namespace for all classes that are considered public.
+// This means that they should be used by apps instead of the internal ownCloud classes
+namespace OCP\Files;
+
+/**
+ * Exception for a file that is locked
+ */
+class LockNotAcquiredException extends \Exception {
+	/** @var string $path The path that could not be locked */
+	public $path;
+
+	/** @var integer $lockType The type of the lock that was attempted */
+	public $lockType;
+
+	public function __construct($path, $lockType, $code = 0, \Exception $previous = null) {
+		$message = \OC_L10N::get('core')->t('Could not obtain lock type %d on "%s".', array($lockType, $path));
+		parent::__construct($message, $code, $previous);
+	}
+
+	// custom string representation of object
+	public function __toString() {
+		return __CLASS__ . ": [{$this->code}]: {$this->message}\n";
+	}
+}
\ No newline at end of file
diff --git a/lib/public/files/storage.php b/lib/public/files/storage.php
index 9bed49c5ab8..6ba1b100249 100644
--- a/lib/public/files/storage.php
+++ b/lib/public/files/storage.php
@@ -317,6 +317,17 @@ interface Storage {
 	public function getETag($path);
 
 	/**
+	 * Returns whether the storage is local, which means that files
+	 * are stored on the local filesystem instead of remotely.
+	 * Calling getLocalFile() for local storages should always
+	 * return the local files, whereas for non-local storages
+	 * it might return a temporary file.
+	 *
+	 * @return bool true if the files are stored locally, false otherwise
+	 */
+	public function isLocal();
+
+	/*
 	 * Check if the storage is an instance of $class or is a wrapper for a storage that is an instance of $class
 	 *
 	 * @param string $class
diff --git a/tests/lib/files/filesystem.php b/tests/lib/files/filesystem.php
index 90f1dfe581b..b0ed065571d 100644
--- a/tests/lib/files/filesystem.php
+++ b/tests/lib/files/filesystem.php
@@ -173,7 +173,7 @@ class Filesystem extends \PHPUnit_Framework_TestCase {
 
 		$homeMount = \OC\Files\Filesystem::getStorage('/' . $userId . '/');
 
-		$this->assertInstanceOf('\OC\Files\Storage\Local', $homeMount);
+		$this->assertTrue($homeMount->instanceOfStorage('\OC\Files\Storage\Local'));
 		$this->assertEquals('local::' . $datadir . '/' . $userId . '/', $homeMount->getId());
 	}
 
@@ -189,7 +189,7 @@ class Filesystem extends \PHPUnit_Framework_TestCase {
 
 		$homeMount = \OC\Files\Filesystem::getStorage('/' . $userId . '/');
 
-		$this->assertInstanceOf('\OC\Files\Storage\Home', $homeMount);
+		$this->assertTrue($homeMount->instanceOfStorage('\OC\Files\Storage\Home'));
 		$this->assertEquals('home::' . $userId, $homeMount->getId());
 
 		\OC_User::deleteUser($userId);
@@ -214,7 +214,7 @@ class Filesystem extends \PHPUnit_Framework_TestCase {
 
 		$homeMount = \OC\Files\Filesystem::getStorage('/' . $userId . '/');
 
-		$this->assertInstanceOf('\OC\Files\Storage\Home', $homeMount);
+		$this->assertTrue($homeMount->instanceOfStorage('\OC\Files\Storage\Home'));
 		$this->assertEquals('local::' . $datadir . '/' . $userId . '/', $homeMount->getId());
 
 		\OC_User::deleteUser($userId);
diff --git a/tests/lib/files/mount/mount.php b/tests/lib/files/mount/mount.php
index b057204ad35..c3d33e0870b 100644
--- a/tests/lib/files/mount/mount.php
+++ b/tests/lib/files/mount/mount.php
@@ -35,7 +35,7 @@ class Mount extends \PHPUnit_Framework_TestCase {
 		};
 
 		$loader = new Loader();
-		$loader->addStorageWrapper($wrapper);
+		$loader->addStorageWrapper('test_wrapper', $wrapper);
 
 		$storage = $this->getMockBuilder('\OC\Files\Storage\Temporary')
 			->disableOriginalConstructor()
diff --git a/tests/lib/util.php b/tests/lib/util.php
index 852caaeccc3..124fb32ed8b 100644
--- a/tests/lib/util.php
+++ b/tests/lib/util.php
@@ -128,7 +128,7 @@ class Test_Util extends PHPUnit_Framework_TestCase {
 
 		$userMount = \OC\Files\Filesystem::getMountManager()->find('/' . $user1 . '/');
 		$this->assertNotNull($userMount);
-		$this->assertInstanceOf('\OC\Files\Storage\Wrapper\Quota', $userMount->getStorage());
+		$this->assertTrue($userMount->getStorage()->instanceOfStorage('\OC\Files\Storage\Wrapper\Quota'));
 
 		// ensure that root wasn't wrapped
 		$rootMount = \OC\Files\Filesystem::getMountManager()->find('/');