"Disk Full" After a Rsync Failure?

So I ran an rsync over night in a tmux sessions. It was to copy contents from one mount to another (USB disks).

Rsync command was:

rsync --info=progress2 /mnt/wdpassport /mnt/wdredpro

When I woke up this morning I saw that my / is completely full. While I'm actually sure it is not.

What can I do to solve this?

Output of: df at the moment of unmounted wdredpro 4tb

Filesystem                         1K-blocks      Used  Available Use% Mounted on
udev                                 8086632         0    8086632   0% /dev
tmpfs                                1626320      5056    1621264   1% /run
/dev/mapper/ubuntu--vg-ubuntu--lv  118882128 118746796          0 100% /
tmpfs                                8131596         0    8131596   0% /dev/shm
tmpfs                                   5120         0       5120   0% /run/lock
tmpfs                                8131596         0    8131596   0% /sys/fs/cgroup
/dev/nvme0n1p2                        999320    207296     723212  23% /boot
/dev/nvme0n1p1                        523248      8036     515212   2% /boot/efi
/dev/loop1                            101760    101760          0 100% /snap/core/11606
/dev/loop2                             56832     56832          0 100% /snap/core18/2074
/dev/loop0                            101888    101888          0 100% /snap/core/11420
/dev/loop3                             69248     69248          0 100% /snap/lxd/20326
/dev/loop4                             33152     33152          0 100% /snap/snapd/12704
/dev/loop6                            103424    103424          0 100% /snap/kotlin/61
/dev/loop5                             33152     33152          0 100% /snap/snapd/12883
/dev/loop7                             72064     72064          0 100% /snap/lxd/21029
/dev/loop8                             56832     56832          0 100% /snap/core18/2128
/dev/loop9                            102912    102912          0 100% /snap/kotlin/60
/dev/sdc2                         1953214336 435989632 1517224704  23% /mnt/wdpassport
tmpfs                                1626316         4    1626312   1% /run/user/1000

Output of: sudo fdisk -l

Disk /dev/loop0: 99.39 MiB, 104210432 bytes, 203536 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/loop1: 99.35 MiB, 104169472 bytes, 203456 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/loop2: 55.45 MiB, 58134528 bytes, 113544 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/loop3: 67.58 MiB, 70848512 bytes, 138376 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/loop4: 32.3 MiB, 33865728 bytes, 66144 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/loop5: 32.31 MiB, 33869824 bytes, 66152 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/loop6: 100.101 MiB, 105889792 bytes, 206816 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/loop7: 70.32 MiB, 73728000 bytes, 144000 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/nvme0n1: 232.91 GiB, 250059350016 bytes, 488397168 sectors
Disk model: Samsung SSD 970 EVO Plus 250GB          
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: BB4634C4-D47E-49AA-8AC6-E576A2308C1A

Device           Start       End   Sectors   Size Type
/dev/nvme0n1p1    2048   1050623   1048576   512M EFI System
/dev/nvme0n1p2 1050624   3147775   2097152     1G Linux filesystem
/dev/nvme0n1p3 3147776 488394751 485246976 231.4G Linux filesystem


Disk /dev/mapper/ubuntu--vg-ubuntu--lv: 115.71 GiB, 124222701568 bytes, 242622464 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/sdb: 3.65 TiB, 4000787030016 bytes, 7814037168 sectors
Disk model: QuickPort Duo Cl
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 1FE11356-27C4-4CA4-9B4F-C41E4875C283

Device     Start        End    Sectors  Size Type
/dev/sdb1   2048 7814035455 7814033408  3.7T Microsoft basic data


Disk /dev/sda: 232.91 GiB, 250059350016 bytes, 488397168 sectors
Disk model: QuickPort Duo Cl
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 1FE11356-27C4-4CA4-9B4F-C41E4875C283

Device      Start       End   Sectors   Size Type
/dev/sda1      40    409639    409600   200M EFI System
/dev/sda2  409640 488392063 487982424 232.7G Microsoft basic data


Disk /dev/sdc: 1.84 TiB, 2000365289472 bytes, 3906963456 sectors
Disk model: My Passport 2626
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 192E2120-52C4-42F8-876B-92EB5E186258

Device      Start        End    Sectors  Size Type
/dev/sdc1      40     409639     409600  200M EFI System
/dev/sdc2  409640 3906961407 3906551768  1.8T Microsoft basic data


Disk /dev/loop8: 55.45 MiB, 58130432 bytes, 113536 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/loop9: 100.49 MiB, 105361408 bytes, 205784 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

Something is not right with the /dev/mapper/ubuntu but not sure how to fix.

When I try to run sudo du -a /home | sort -n -r | head -n 20 to see where the biggest files are coming from I'm getting this output:

sort: write failed: /tmp/sortDfVeHU: No space left on device