From 5d22078f3592e6b3914ec037a8dc86c5572cd868 Mon Sep 17 00:00:00 2001
From: Thomas Waldmann <tw@waldmann-edv.de>
Date: Thu, 15 Sep 2016 14:56:11 +0200
Subject: [PATCH] fuse: add parameter check to ItemCache.get to make potential
 failures more clear

---
 src/borg/fuse.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/borg/fuse.py b/src/borg/fuse.py
index 47b8568b1..8e3a8e4da 100644
--- a/src/borg/fuse.py
+++ b/src/borg/fuse.py
@@ -43,7 +43,10 @@ class ItemCache:
         return pos + self.offset
 
     def get(self, inode):
-        self.fd.seek(inode - self.offset, io.SEEK_SET)
+        offset = inode - self.offset
+        if offset < 0:
+            raise ValueError('ItemCache.get() called with an invalid inode number')
+        self.fd.seek(offset, io.SEEK_SET)
         item = next(msgpack.Unpacker(self.fd, read_size=1024))
         return Item(internal_dict=item)