(Mix) Unpacking tarball failed:

I got the elixir phoenix error on WSL2 as bellow.
** (Mix) Unpacking tarball failed: inner tarball error, not owner

It was not inthe linux directory but on the Windows file system accessing through the /mnt/c/ . I was guessing it was the reason.

$ mix deps.get
Resolving Hex dependencies...
Dependency resolution completed:
New:
...
...
* Updating phoenix (Hex package)
** (Mix) Unpacking tarball failed: inner tarball error, not owner

solution. Mount C: with the drvfs type.

$sudo umount /mnt/c
$sudo mount -t drvfs C: /mnt/c -o metadata

see the official blog post from microsoft

DrvFs is a filesystem plugin to WSL that was designed to support interop between WSL and the Windows filesystem. DrvFs enables WSL to mount drives with supported file systems under /mnt, such as /mnt/c, /mnt/d, etc. 

So inside mix deps.get, sometime write permissions were  required and it caused the error before.
Note that this mount with drvfs should be performed each time starting WSL.

and I feel it is really slow to process compiling ...