From 2fbb504b66509668d95d49ef94cbd475f16587ea Mon Sep 17 00:00:00 2001
From: Nick Craig-Wood <nick@craig-wood.com>
Date: Thu, 14 Mar 2019 21:19:47 +0000
Subject: [PATCH] webdav: fix About/df when reading the available/total returns
 0

Some WebDAV servers return an empty Available and Used which parses as 0.

This caused About to return the Total as 0 which can confused mounted
file systems.

After this change we ignore the result if Available and Used are both 0.

See: https://forum.rclone.org/t/windows-mounted-webdav-drive-has-no-free-space/8938
---
 backend/webdav/webdav.go | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/backend/webdav/webdav.go b/backend/webdav/webdav.go
index 96b8a053b..de1e9f3b3 100644
--- a/backend/webdav/webdav.go
+++ b/backend/webdav/webdav.go
@@ -916,11 +916,13 @@ func (f *Fs) About() (*fs.Usage, error) {
 		return nil, errors.Wrap(err, "about call failed")
 	}
 	usage := &fs.Usage{}
-	if q.Available >= 0 && q.Used >= 0 {
-		usage.Total = fs.NewUsageValue(q.Available + q.Used)
-	}
-	if q.Used >= 0 {
-		usage.Used = fs.NewUsageValue(q.Used)
+	if q.Available != 0 || q.Used != 0 {
+		if q.Available >= 0 && q.Used >= 0 {
+			usage.Total = fs.NewUsageValue(q.Available + q.Used)
+		}
+		if q.Used >= 0 {
+			usage.Used = fs.NewUsageValue(q.Used)
+		}
 	}
 	return usage, nil
 }