From 7a689b1295ca647a7f9008df508f303214930d08 Mon Sep 17 00:00:00 2001
From: Thomas Waldmann <tw@waldmann-edv.de>
Date: Tue, 10 Oct 2017 00:51:13 +0200
Subject: [PATCH] don't crash in first part of truncate_and_unlink, fixes #3117

---
 src/borg/helpers/fs.py | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/borg/helpers/fs.py b/src/borg/helpers/fs.py
index 783c14d7a..465c4c110 100644
--- a/src/borg/helpers/fs.py
+++ b/src/borg/helpers/fs.py
@@ -1,3 +1,4 @@
+import errno
 import os
 import os.path
 import re
@@ -141,8 +142,13 @@ def truncate_and_unlink(path):
     recover. Refer to the "File system interaction" section
     in repository.py for further explanations.
     """
-    with open(path, 'r+b') as fd:
-        fd.truncate()
+    try:
+        with open(path, 'r+b') as fd:
+            fd.truncate()
+    except OSError as err:
+        if err.errno != errno.ENOTSUP:
+            raise
+        # don't crash if the above ops are not supported.
     os.unlink(path)