Index: uspace/srv/vfs/vfs_ops.c
===================================================================
--- uspace/srv/vfs/vfs_ops.c	(revision db4ec8d433d5a57e9661bceeab3b1ffff2adb1ff)
+++ uspace/srv/vfs/vfs_ops.c	(revision 18825251b8c3e8e97adbfdaa2ea5343181835914)
@@ -1355,4 +1355,5 @@
 		int ret = vfs_close_internal(newfile);
 		if (ret != EOK) {
+			fibril_mutex_unlock(&oldfile->lock);
 			ipc_answer_0(rid, ret);
 			return;
@@ -1361,4 +1362,5 @@
 		ret = vfs_fd_free(newfd);
 		if (ret != EOK) {
+			fibril_mutex_unlock(&oldfile->lock);
 			ipc_answer_0(rid, ret);
 			return;