I was using these instructions to setup an external hard disk with udf. I have been able to setup a multi-partition system using those instructions, but I seem to have hit a wall, where the partition is reported as full while writing to the disk. Every other tool available to me reports it as free.

• Relevant lshw output

Here's a screenshot showing the disk:

Both the output of df and the file manager (caja) report the disk as free.

Filesystem      Size  Used Avail Use% Mounted on
/dev/sda9       9.0G  7.6G  910M  90% /
udev            974M   12K  974M   1% /dev
/dev/sda1        50G   47G  295M 100% /media/Data
/dev/sda6        49G   41G  5.9G  88% /home
/dev/sda2       155G  127G   29G  82% /media/Entertainment
/dev/sda8        14G   13G  516M  96% /media/Stuff
/dev/sdb2       120G  1.9G  112G   2% /media/3c887659-5676-4946-875b-b797be508ce7
/dev/sdb3        11G  2.6G  7.7G  25% /media/108b0a1d-fd1a-4f38-b1c6-4ad1a20e34a3
/dev/sdb1       802G   34G  768G   5% /media/disk

I seem to have hit a wall near the 35GB mark. Despite being shown as 35gb/860gb used everywhere, the following happens on a write attempt:

[2017][/media/Dory]$ echo D>>echo
bash: echo: write error: No space left on device

Writing byte by byte, the maximum I can take it to is 34719248K.

The most weird part is that on mounting it Windows, Windows can write to the disk easily, and the writes are being read fine back in Ubuntu. However, the used-bytes remains at 34719248K in Ubuntu (It goes higher on Windows, however).