Enhance quota exceeded logging for admins

apps/dav/lib/Connector/Sabre/QuotaPlugin.php

@@ -202,12 +202,27 @@ public function checkQuota($path, $length = null) {
 				// use target file name for free space check in case of shared files
 				$path = rtrim($parentPath, '/') . '/' . $info['name'];
 			}
+
+			// TODO: I suspect the below existence check more properly belongs in
+			//      beforeCreateFile(), similar to what already exists in
+			//      beforeCopy and beforeMove()
+			// NOTE: && or || here is equivalent in terms of outcome (but && our intention)
+			//      because only other times the full path SHOULD get to us here is when 
+			//      existence has already been confirmed - see beforeCopy() & beforeMove())
+			if (!$req->getHeader('Destination') && !$this->server->tree->nodeExists($path)) {
+				$path = dirname($path);
+			}
+			$targetOwner = $this->view->getOwner($path);
 			$freeSpace = $this->getFreeSpace($path);
 			if ($freeSpace >= 0 && $length > $freeSpace) {
 				if (isset($chunkHandler)) {
 					$chunkHandler->cleanup();
 				}
-				throw new InsufficientStorage("Insufficient space in $path, $length required, $freeSpace available");
+				if ($targetOwner !== \OC_User::getUser()) {
+					throw new InsufficientStorage("Quota exceeded in $path (owner: $targetOwner), $length required, $freeSpace available");
+				} else {
+					throw new InsufficientStorage("Quota exceeded in $path, $length required, $freeSpace available");
+				}
 			}
 		}
 		return true;

apps/dav/tests/unit/Connector/Sabre/QuotaPluginTest.php

@@ -41,6 +41,14 @@
  * later.
  * See the COPYING-README file.
  */
+
+/**
+ * Class QuotaPluginTest
+ *
+ * @group DB
+ *
+ */
+
 class QuotaPluginTest extends TestCase {
 
 	/** @var \Sabre\DAV\Server | \PHPUnit\Framework\MockObject\MockObject */