Btrfs-progs: fall back to the v1 ioctl if the new balance ioctl fails

This only falls back if the plain version of balance start is used.
Any args make us report the ioctl isn't supported.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
1 file changed