diff --git a/files/ajax/upload.php b/files/ajax/upload.php
index 5dcd2f2b6a..4247aeca28 100644
--- a/files/ajax/upload.php
+++ b/files/ajax/upload.php
@@ -19,6 +19,16 @@ $files=$_FILES['files'];
 $dir = $_POST['dir'];
 if(!empty($dir)) $dir .= '/';
 $error='';
+
+$totalSize=0;
+foreach($files['size'] as $size){
+	$totalSize+=$size;
+}
+if($totalSize>OC_Filesystem::free_space('/')){
+	echo json_encode( array( "status" => "error", "data" => array( "message" => "Not enough space available" )));
+	exit();
+}
+
 $result=array();
 if(strpos($dir,'..') === false){
 	$fileCount=count($files['name']);
diff --git a/lib/fileproxy.php b/lib/fileproxy.php
new file mode 100644
index 0000000000..549b7015a6
--- /dev/null
+++ b/lib/fileproxy.php
@@ -0,0 +1,111 @@
+<?php
+
+/**
+* ownCloud
+*
+* @author Robin Appelman
+* @copyright 2011 Robin Appelman icewind1991@gmail.com
+*
+* 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/>.
+*
+*/
+
+/**
+ * Class for manipulating filesystem requests
+ *
+ * Manipulation happens by using 2 kind of proxy operations, pre and post proxies
+ * that manipulate the filesystem call and the result of the call respectively
+ *
+ * A pre-proxy recieves the filepath as arugments (or 2 filespaths in case of operations like copy or move) and return a boolean
+ * If a pre-proxy returnes false the file operation will be canceled
+ * All filesystem operations have a pre-proxy
+ *
+ * A post-proxy recieves 2 arguments, the filepath and the result of the operation.
+ * The return calue of the post-proxy will be used as the new result of the operation
+ * The operations that have a post-proxy are
+ *      file_get_contents, is_file, is_dir, file_exists, stat, is_readable, is_writable, fileatime, filemtime, filectime, file_get_contents, getMimeType, hash, free_space and search
+ */
+
+class OC_FileProxy{
+	private static $proxies=array();
+	
+	/**
+	 * check if this proxy implments a specific proxy operation
+	 * @param string #proxy name of the proxy operation
+	 * @return bool
+	 */
+	public function provides($operation){
+		return method_exists($this,$operation);
+	}
+	
+	/**
+	 * fallback function when a proxy operation is not implement
+	 * @param string $function the name of the proxy operation
+	 * @param mixed
+	 *
+	 * this implements a dummy proxy for all operations
+	 */
+	public function __call($function,$arguments){
+		if(substr($function,0,3)=='pre'){
+			return true;
+		}else{
+			return $arguments[1];
+		}
+	}
+	
+	/**
+	 * register a proxy to be used
+	 * @param OC_FileProxy $proxy
+	 */
+	public static function register($proxy){
+		self::$proxies[]=$proxy;
+	}
+	
+	public static function getProxies($operation,$post){
+		$operation=(($post)?'post':'pre').$operation;
+		$proxies=array();
+		foreach(self::$proxies as $proxy){
+			if($proxy->provides($operation)){
+				$proxies[]=$proxy;
+			}
+		}
+		return $proxies;
+	}
+
+	public static function runPreProxies($operation,$filepath,$filepath2=null){
+		$proxies=self::getProxies($operation,false);
+		$operation='pre'.$operation;
+		foreach($proxies as $proxy){
+			if($filepath2){
+				if(!$proxy->$operation($filepath,$filepath2)){
+					return false;
+				}
+			}else{
+				if(!$proxy->$operation($filepath)){
+					return false;
+				}
+			}
+		}
+		return true;
+	}
+
+	public static function runPostProxies($operation,$path,$result){
+		$proxies=self::getProxies($operation,true);
+		$operation='post'.$operation;
+		foreach($proxies as $proxy){
+			$result=$proxy->$operation($path,$result);
+		}
+		return $result;
+	}
+}
\ No newline at end of file
diff --git a/lib/fileproxy/quota.php b/lib/fileproxy/quota.php
new file mode 100644
index 0000000000..af8ddee147
--- /dev/null
+++ b/lib/fileproxy/quota.php
@@ -0,0 +1,61 @@
+<?php
+
+/**
+* ownCloud
+*
+* @author Robin Appelman
+* @copyright 2011 Robin Appelman icewind1991@gmail.com
+*
+* 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/>.
+*
+*/
+
+/**
+ * user quota managment
+ */
+
+class OC_FileProxy_Quota extends OC_FileProxy{
+	private function getFreeSpace(){
+		$usedSpace=OC_Filesystem::filesize('');
+		$totalSpace=OC_Preferences::getValue(OC_User::getUser(),'files','quota',0);
+		if($totalSpace==0){
+			return 0;
+		}
+		return $totalSpace-$usedSpace;
+	}
+	
+	public function postFree_space($path,$space){
+		$free=$this->getFreeSpace();
+		if($free==0){
+			return $space;
+		}
+		return min($free,$space);
+	}
+
+	public function preFile_put_contents($path,$data){
+		return (strlen($data)<$this->getFreeSpace() or $this->getFreeSpace()==0);
+	}
+
+	public function preCopy($path1,$path2){
+		return (OC_Filesystem::filesize($path1)<$this->getFreeSpace() or $this->getFreeSpace()==0);
+	}
+
+	public function preFromTmpFile($tmpfile,$path){
+		return (filesize($tmpfile)<$this->getFreeSpace() or $this->getFreeSpace()==0);
+	}
+
+	public function preFromUploadedFile($tmpfile,$path){
+		return (filesize($tmpfile)<$this->getFreeSpace() or $this->getFreeSpace()==0);
+	}
+}
\ No newline at end of file
diff --git a/lib/filesystem.php b/lib/filesystem.php
index a688c9c2b0..911a85e4a3 100644
--- a/lib/filesystem.php
+++ b/lib/filesystem.php
@@ -228,150 +228,71 @@ class OC_Filesystem{
 	}
 	
 	static public function mkdir($path){
-		$parent=substr($path,0,strrpos($path,'/'));
-		if(self::canWrite($parent) and $storage=self::getStorage($path)){
-			$run=true;
-			OC_Hook::emit( 'OC_Filesystem', 'create', array( 'path' => $path, 'run' => &$run));
-			if($run){
-				OC_Hook::emit( 'OC_Filesystem', 'write', array( 'path' => $path, 'run' => &$run));
-			}
-			if($run){
-				$result=$storage->mkdir(self::getInternalPath($path));
-				OC_Hook::emit( 'OC_Filesystem', 'post_create', array( 'path' => $path));
-				OC_Hook::emit( 'OC_Filesystem', 'post_write', array( 'path' => $path));
-				return $result;
-			}
-		}
+		return self::basicOperation('mkdir',$path,array('create','write'));
 	}
 	static public function rmdir($path){
-		if(self::canWrite($path) and $storage=self::getStorage($path)){
-			$run=true;
-			OC_Hook::emit( 'OC_Filesystem', 'delete', array( 'path' => $path, 'run' => &$run));
-			if($run){
-				$result=$storage->rmdir(self::getInternalPath($path));
-				OC_Hook::emit( 'OC_Filesystem', 'post_delete', array( 'path' => $path));
-				return $result;
-			}
-		}
+		return self::basicOperation('rmdir',$path,array('delete'));
 	}
 	static public function opendir($path){
-		if(self::canRead($path) and $storage=self::getStorage($path)){
-			OC_Hook::emit( 'OC_Filesystem', 'read', array( 'path' => $path));
-			return $storage->opendir(self::getInternalPath($path));
-		}
+		return self::basicOperation('opendir',$path,array('read'));
 	}
 	static public function is_dir($path){
 		if($path=='/'){
 			return true;
 		}
-		if(self::canRead($path) and $storage=self::getStorage($path)){
-			return $storage->is_dir(self::getInternalPath($path));
-		}
+		return self::basicOperation('is_dir',$path);
 	}
 	static public function is_file($path){
 		if($path=='/'){
 			return false;
 		}
-		if(self::canRead($path) and $storage=self::getStorage($path)){
-			return $storage->is_file(self::getInternalPath($path));
-		}
+		return self::basicOperation('is_file',$path);
 	}
 	static public function stat($path){
-		if(self::canRead($path) and $storage=self::getStorage($path)){
-			return $storage->stat(self::getInternalPath($path));
-		}
+		return self::basicOperation('stat',$path);
 	}
 	static public function filetype($path){
-		if(self::canRead($path) and $storage=self::getStorage($path)){
-			return $storage->filetype(self::getInternalPath($path));
-		}
+		return self::basicOperation('filetype',$path);
 	}
 	static public function filesize($path){
-		if(self::canRead($path) and $storage=self::getStorage($path)){
-			return $storage->filesize(self::getInternalPath($path));
-		}
+		return self::basicOperation('filesize',$path);
 	}
 	static public function readfile($path){
-		if(self::canRead($path) and $storage=self::getStorage($path)){
-			OC_Hook::emit( 'OC_Filesystem', 'read', array( 'path' => $path));
-			return $storage->readfile(self::getInternalPath($path));
-		}
+		return self::basicOperation('readfile',$path,array('read'));
 	}
 	static public function is_readable($path){
-		if(self::canRead($path) and $storage=self::getStorage($path)){
-			return $storage->is_readable(self::getInternalPath($path));
-		}
-		return false;
+		return self::basicOperation('is_readable',$path);
 	}
 	static public function is_writeable($path){
-		if(self::canWrite($path) and $storage=self::getStorage($path)){
-			return $storage->is_writeable(self::getInternalPath($path));
-		}
-		return false;
+		return self::basicOperation('is_writeable',$path);
 	}
 	static public function file_exists($path){
 		if($path=='/'){
 			return true;
 		}
-		if(self::canWrite($path) and $storage=self::getStorage($path)){
-			return $storage->file_exists(self::getInternalPath($path));
-		}
-		return false;
+		return self::basicOperation('file_exists',$path);
 	}
 	static public function filectime($path){
-		if($storage=self::getStorage($path)){
-			return $storage->filectime(self::getInternalPath($path));
-		}
+		return self::basicOperation('filectime',$path);
 	}
 	static public function filemtime($path){
-		if($storage=self::getStorage($path)){
-			return $storage->filemtime(self::getInternalPath($path));
-		}
+		return self::basicOperation('filemtime',$path);
 	}
 	static public function fileatime($path){
-		if($storage=self::getStorage($path)){
-			return $storage->fileatime(self::getInternalPath($path));
-		}
+		return self::basicOperation('fileatime',$path);
 	}
 	static public function file_get_contents($path){
-		if(self::canRead($path) and $storage=self::getStorage($path)){
-			OC_Hook::emit( 'OC_Filesystem', 'read', array( 'path' => $path));
-			return $storage->file_get_contents(self::getInternalPath($path));
-		}
+		return self::basicOperation('file_get_contents',$path,array('read'));
 	}
 	static public function file_put_contents($path,$data){
-		if(self::canWrite($path) and $storage=self::getStorage($path)){
-			$run=true;
-			$exists=self::file_exists($path);
-			if(!$exists){
-				OC_Hook::emit( 'OC_Filesystem', 'create', array( 'path' => $path, 'run' => &$run));
-			}
-			if($run){
-				OC_Hook::emit( 'OC_Filesystem', 'write', array( 'path' => $path, 'run' => &$run));
-			}
-			if($run){
-				$result=$storage->file_put_contents(self::getInternalPath($path),$data);
-				if(!$exists){
-					OC_Hook::emit( 'OC_Filesystem', 'post_create', array( 'path' => $path));
-				}
-				OC_Hook::emit( 'OC_Filesystem', 'post_write', array( 'path' => $path));
-				return $result;
-			}
-		}
+		error_log($data);
+		return self::basicOperation('file_put_contents',$path,array('create','write'),$data);
 	}
 	static public function unlink($path){
-		if(self::canWrite($path) and $storage=self::getStorage($path)){
-			$run=true;
-			OC_Hook::emit( 'OC_Filesystem', 'delete', array( 'path' => $path, 'run' => &$run));
-			if($run){
-				$result=$storage->unlink(self::getInternalPath($path));
-				OC_Hook::emit( 'OC_Filesystem', 'post_delete', array( 'path' => $path));
-				return $result;
-			}
-		}
+		return self::basicOperation('unlink',$path,array('delete'));
 	}
 	static public function rename($path1,$path2){
-		if(self::canWrite($path1) and self::canWrite($path2)){
+		if(OC_FileProxy::runPreProxies('rename',$path1,$path2) and self::canWrite($path1) and self::canWrite($path2)){
 			$run=true;
 			OC_Hook::emit( 'OC_Filesystem', 'rename', array( 'oldpath' => $path1 ,'newpath'=>$path2, 'run' => &$run));
 			if($run){
@@ -392,7 +313,7 @@ class OC_Filesystem{
 		}
 	}
 	static public function copy($path1,$path2){
-		if(self::canRead($path1) and self::canWrite($path2)){
+		if(OC_FileProxy::runPreProxies('copy',$path1,$path2) and self::canRead($path1) and self::canWrite($path2)){
 			$run=true;
 			OC_Hook::emit( 'OC_Filesystem', 'copy', array( 'oldpath' => $path1 ,'newpath'=>$path2, 'run' => &$run));
 			$exists=self::file_exists($path2);
@@ -423,60 +344,35 @@ class OC_Filesystem{
 		}
 	}
 	static public function fopen($path,$mode){
-		$allowed=((strpos($path,'r')===false and strpos($path,'r+')!==false and self::canRead) or self::canWrite($path));
-		if($allowed){
-			if($storage=self::getStorage($path)){
-				$run=true;
-				$exists=self::file_exists($path);
-				$write=false;
-				switch($mode){
-					case 'r':
-						OC_Hook::emit( 'OC_Filesystem', 'read', array( 'path' => $path));
-						break;
-					case 'r+':
-					case 'w+':
-					case 'x+':
-					case 'a+':
-						OC_Hook::emit( 'OC_Filesystem', 'read', array( 'path' => $path));
-						$write=true;
-						break;
-					case 'w':
-					case 'x':
-					case 'a':
-						$write=true;
-						break;
-				}
-				if($write){
-					if(!$exists){
-						OC_Hook::emit( 'OC_Filesystem', 'create', array( 'path' => $path));
-					}
-					if($run){
-						OC_Hook::emit( 'OC_Filesystem', 'write', array( 'path' => $path, 'run' => &$run));
-					}
-				}
-				if($run){
-					$result=$storage->fopen(self::getInternalPath($path),$mode);
-					if($write){
-						if(!$exists){
-							OC_Hook::emit( 'OC_Filesystem', 'post_create', array( 'path' => $path));
-						}
-						if($run){
-							OC_Hook::emit( 'OC_Filesystem', 'post_write', array( 'path' => $path));
-						}
-					}
-					return $result;
-				}
-			}
+		$hooks=array();
+		switch($mode){
+			case 'r':
+				$hooks[]='read';
+				break;
+			case 'r+':
+			case 'w+':
+			case 'x+':
+			case 'a+':
+				$hooks[]='read';
+				$hooks[]='write';
+				break;
+			case 'w':
+			case 'x':
+			case 'a':
+				$hooks[]='write';
+				break;
 		}
+		
+		return self::basicOperation('fopen',$path,$hooks);
 	}
 	static public function toTmpFile($path){
-		if(self::canRead($path) and $storage=self::getStorage($path)){
+		if(OC_FileProxy::runPreProxies('toTmpFile',$path) and self::canRead($path) and $storage=self::getStorage($path)){
 			OC_Hook::emit( 'OC_Filesystem', 'read', array( 'path' => $path));
 			return $storage->toTmpFile(self::getInternalPath($path));
 		}
 	}
 	static public function fromTmpFile($tmpFile,$path){
-		if(self::canWrite($path) and $storage=self::getStorage($path)){
+		if(OC_FileProxy::runPreProxies('copy',$tmpFile,$path) and self::canWrite($path) and $storage=self::getStorage($path)){
 			$run=true;
 			$exists=self::file_exists($path);
 			if(!$exists){
@@ -497,7 +393,7 @@ class OC_Filesystem{
 	}
 	static public function fromUploadedFile($tmpFile,$path){
 		error_log('upload');
-		if(self::canWrite($path) and $storage=self::getStorage($path)){
+		if(OC_FileProxy::runPreProxies('fromUploadedFile',$tmpFile,$path) and self::canWrite($path) and $storage=self::getStorage($path)){
 			$run=true;
 			$exists=self::file_exists($path);
 			if(!$exists){
@@ -518,57 +414,14 @@ class OC_Filesystem{
 		}
 	}
 	static public function getMimeType($path){
-		if(self::canRead($path) and $storage=self::getStorage($path)){
-			return $storage->getMimeType(self::getInternalPath($path));
-		}
+		return self::basicOperation('getMimeType',$path);
 	}
-	static public function delTree($path){
-		if(self::canWrite($path) and $storage=self::getStorage($path)){
-			$run=true;
-			OC_Hook::emit( 'OC_Filesystem', 'delete', array( 'path' => $path, 'run' => &$run));
-			if($run){
-				return $storage->delTree(self::getInternalPath($path));
-			}
-		}
-	}
-	static public function find($path){
-		if($storage=self::getStorage($path)){
-			$mp=self::getMountPoint($path);
-			$return=$storage->find(self::getInternalPath($path));
-			foreach($return as &$file){
-				$file=$mp.$file;
-			}
-		}
-		return $return;
-	}
-	static public function getTree($path){
-		if(self::canRead($path) and $storage=self::getStorage($path)){
-			$mp=self::getMountPoint($path);
-			$return=$storage->getTree(self::getInternalPath($path));
-			foreach($return as &$file){
-				if(substr($file,0,1)=='/'){
-					$file=substr($file,1);
-				}
-				$file=$mp.$file;
-				$file=substr($file,strlen(self::$fakeRoot));
-				if($file === '' || $file === false){
-					$file = '/';
-				}
-			}
-			return $return;
-		}
-	}
-	static public function hash($type,$path,$raw=false){
-		if(self::canRead($path) and $storage=self::getStorage($path)){
-			OC_Hook::emit( 'OC_Filesystem', 'read', array( 'path' => $path));
-			return $storage->hash($type,self::getInternalPath($path),$raw);
-		}
+	static public function hash($type,$path){
+		return self::basicOperation('hash',$path,array('read'));
 	}
 	
 	static public function free_space($path='/'){
-		if(self::canRead($path) and $storage=self::getStorage($path)){
-			return $storage->free_space($path);
-		}
+		return self::basicOperation('free_space',$path);
 	}
 	
 	static public function search($query){
@@ -590,4 +443,41 @@ class OC_Filesystem{
 		return $files;
 		
 	}
+
+	/**
+	 * abstraction for running most basic operations
+	 * @param string $operation
+	 * @param string #path
+	 * @param array (optional) hooks
+	 * @param mixed (optional) $extraParam
+	 * @return mixed
+	 */
+	private static function basicOperation($operation,$path,$hooks=array(),$extraParam=null){
+		if(OC_FileProxy::runPreProxies($operation,$path) and self::canRead($path) and $storage=self::getStorage($path)){
+			$interalPath=self::getInternalPath($path);
+			$run=true;
+			foreach($hooks as $hook){
+				if($hook!='read'){
+					OC_Hook::emit( 'OC_Filesystem', $hook, array( 'path' => $path, 'run' => &$run));
+				}else{
+					OC_Hook::emit( 'OC_Filesystem', $hook, array( 'path' => $path));
+				}
+			}
+			if($run){
+				if($extraParam){
+					$result=$storage->$operation($interalPath,$extraParam);
+				}else{
+					$result=$storage->$operation($interalPath);
+				}
+				$result=OC_FileProxy::runPostProxies($operation,$path,$result);
+				foreach($hooks as $hook){
+					if($hook!='read'){
+						OC_Hook::emit( 'OC_Filesystem', 'post_'.$hook, array( 'path' => $path));
+					}
+				}
+				return $result;
+			}
+		}
+		return null;
+	}
 }
diff --git a/lib/util.php b/lib/util.php
index 83d39b3dd2..0fdfa01230 100644
--- a/lib/util.php
+++ b/lib/util.php
@@ -74,6 +74,8 @@ class OC_Util {
 
 			//jail the user into his "home" directory
 			OC_Filesystem::chroot("/$user/$root");
+			$quotaProxy=new OC_FileProxy_Quota();
+			OC_FileProxy::register($quotaProxy);
 			self::$fsSetup=true;
 		}
 	}