Merge remote-tracking branch 'origin/master' into filecache-extension

1 files changed, 15 insertions, 3 deletions

diff --git a/apps/dav/lib/Connector/Sabre/File.php b/apps/dav/lib/Connector/Sabre/File.php
index bc72fd24e71..3ce305d75f3 100644
--- a/apps/dav/lib/Connector/Sabre/File.php
+++ b/apps/dav/lib/Connector/Sabre/File.php
@@ -252,10 +252,22 @@ class File extends Node implements IFile {
 				try {
 					$this->changeLock(ILockingProvider::LOCK_EXCLUSIVE);
 				} catch (LockedException $e) {
-					if ($needsPartFile) {
-						$partStorage->unlink($internalPartPath);
+					// during very large uploads, the shared lock we got at the start might have been expired
+					// meaning that the above lock can fail not just only because somebody else got a shared lock
+					// or because there is no existing shared lock to make exclusive
+					//
+					// Thus we try to get a new exclusive lock, if the original lock failed because of a different shared
+					// lock this will still fail, if our original shared lock expired the new lock will be successful and
+					// the entire operation will be safe
+
+					try {
+						$this->acquireLock(ILockingProvider::LOCK_EXCLUSIVE);
+					} catch (LockedException $e) {
+						if ($needsPartFile) {
+							$partStorage->unlink($internalPartPath);
+						}
+						throw new FileLocked($e->getMessage(), $e->getCode(), $e);
 					}
-					throw new FileLocked($e->getMessage(), $e->getCode(), $e);
 				}
 
 				// rename to correct path