1a - Shrink /dev/sdc1 of btrfs on /dev/sdc1 (10.00 GiB) and /dev/sdd1 (10.00 GiB) from 10.00 GiB to 9.00 GiB -> 1b
1b - Shrink partition /dev/sdc1 from 10.00 GiB to 9.00 GiB ->

2a - Shrink /dev/sdd1 of btrfs on /dev/sdc1 (10.00 GiB) and /dev/sdd1 (10.00 GiB) from 10.00 GiB to 9.00 GiB -> 2b
2b - Shrink partition /dev/sdd1 from 10.00 GiB to 9.00 GiB ->
