From b9b9bce0db64abdfabc9fbdca26416e40400eb93 Mon Sep 17 00:00:00 2001
From: Nick Craig-Wood <nick@craig-wood.com>
Date: Thu, 28 Jun 2018 09:01:17 +0100
Subject: [PATCH] ftp: fix Put mkParentDir failed: 521 for BunnyCDN - fixes
 #2363

According to RFC 959, error 521 is the correct error return to mean
"dir already exists", so add support for this.
---
 backend/ftp/ftp.go | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/backend/ftp/ftp.go b/backend/ftp/ftp.go
index a06f977f0..1066fd0b4 100644
--- a/backend/ftp/ftp.go
+++ b/backend/ftp/ftp.go
@@ -480,6 +480,8 @@ func (f *Fs) mkdir(abspath string) error {
 		switch errX.Code {
 		case ftp.StatusFileUnavailable: // dir already exists: see issue #2181
 			err = nil
+		case 521: // dir already exists: error number according to RFC 959: issue #2363
+			err = nil
 		}
 	}
 	return err