Answer by Kamil Maciorowski for How to determine the use of a mystery partition and whether it can be deleted?

About parted

"Partition Table: loop" is parted's way of saying that there is actually no partition table. Misleading, I know.

Not having a partition table is totally normal in this case, because your nvme0n1p2 is itself a partition of nvme0n1 and nested partition tables are possible in principle, but not supported in practice. Having a partition table inside nvme0n1p2 would be way more mysterious than not having one.

About df

df reports space usage of mounted filesystem(s). It does not peek into devices. When given a pathname, it will tell you about the filesystem the path belongs to. It so happens /dev/nvme0n1p2 you gave to df is a path to a device file placed inside /dev. /dev is the mountpoint of the filesystem (of type udev) holding the device file.

To see the space usage of the filesystem (if any) existing inside /dev/nvme0n1p2, you need to mount the filesystem and either give df the pathname of the mountpoint (or of any file under the mountpoint) or invoke df without any operand.

How to proceed

• Examining /dev/nvme0n1 with parted (or with a similar tool) will show you /dev/nvme0n1p2 as a partition and may give you some clue.

• gparted and parted have already told you "ext4" about nvme0n1p2. Expect the below commands to confirm that there is a filesystem of this type inside the partition:

  • sudo file -skr /dev/nvme0n1p2

  • sudo blkid /dev/nvme0n1p2

• If the above commands indeed find a filesystem inside nvme0n1p2 then you can try to mount:

  sudo mount -o ro /dev/nvme0n1p2 /some/mountpoint

  and investigate what's inside. Now df /some/mountpoint will be useful.