On Tue, Oct 19, 2021 at 08:23:43AM +0800, Anand Jain wrote:

The following test case fails as it trying to read the fsid from the sb
for a missing device.

   $ mkfs.btrfs -f -draid1 -mraid1 $DEV1 $DEV2 
   $ btrfstune -S 1 $DEV1 
   $ wipefs -a $DEV2 
   $ btrfs dev scan --forget 
   $ mount -o degraded $DEV1 /btrfs 
   $ btrfs device add $DEV3 /btrfs -f 

   $ btrfs fi us /btrfs 
     ERROR: unexpected number of devices: 1 >= 1 
     ERROR: if seed device is used, try running this command as root
 

I'd like to see this as either a btrfs-progs test or an fstest.  I think I
prefer the fstest because you're adding a sysfs file, so maybe a couple of
tests, one to validate the sysfs file behaves properly, and then one to do this
test as well.  Thanks,

Josef