From fd2e59929bb4d3d786d68719cf0cfafd528f2a1d Mon Sep 17 00:00:00 2001
From: Mehran Kholdi <semekh@hamravesh.com>
Date: Mon, 1 Mar 2021 13:40:06 +0330
Subject: [PATCH] Fix bug with online resizing btrfs filesystems having
 non-default subvol

```
Command 'losetup -c /dev/loop0[/default]' returned non-zero exit status 1.
```
---
 metrics.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/metrics.py b/metrics.py
index fd18d16..93a64a7 100644
--- a/metrics.py
+++ b/metrics.py
@@ -40,7 +40,7 @@ def dev_to_mountpoint(dev_name):
 
 def mountpoint_to_dev(mountpoint):
     res = subprocess.run(
-        f"findmnt --json --first-only --mountpoint {mountpoint}",
+        f"findmnt --json --first-only --nofsroot --mountpoint {mountpoint}",
         shell=True,
         capture_output=True,
     )