Index: uspace/srv/vfs/vfs_ops.c
===================================================================
--- uspace/srv/vfs/vfs_ops.c	(revision c7a8442ca3b47932cb646a789c90c21a68d739cc)
+++ uspace/srv/vfs/vfs_ops.c	(revision c0e74b13d7e036bbd53eaf5b45055d2eb8907678)
@@ -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;