On Thu, 17 Dec 2020 13:30:08 +0100 Ulli Horlacher <[email protected]> wrote:
> root@fextest:/nfs/rusnas/fex# mount disk1.btrfs /mnt/tmp > root@fextest:/nfs/rusnas/fex# df -TH /mnt/tmp > Filesystem Type Size Used Avail Use% Mounted on > /dev/loop2 btrfs 16T 3.7M 16T 1% /mnt/tmp You see here 'mount' has transparently created a 'loop device' for you in order to mount the FS. > Now I want to extend this filesystem, but this approach fails: > > root@fextest:/nfs/rusnas/fex# touch disk2.btrfs > root@fextest:/nfs/rusnas/fex# truncate -s 16TB disk2.btrfs > root@fextest:/nfs/rusnas/fex# btrfs device add /nfs/rusnas/fex/disk2.btrfs > /mnt/tmp > ERROR: /nfs/rusnas/fex/disk2.btrfs is not a block device Since file is not a block device, here you have to do the same manually. See documentation for 'losetup'. -- With respect, Roman
