On 13.09.2018 19:15, Serhat Sevki Dincer wrote:
>> -1 seems to be EPERM, is your device write-protected, readonly or
>> something like that ?
>
> I am able to use ext4 partition read/write, created a file and wrote
> in it, un/re mounted it, all is ok.
> The drive only has a microusb port and a little led light; no rw
> switch or anything like that..
>
What might help is running btrfs convert under strace. So something like :
sudo strace -f -o strace.log btrfs-convert /dev/sdb1 and then send the log.
