[PATCH] erofs-utils: tar: support archives without end-of-archive entry

[Ivan Mikheykin]

Hello!

On 9/29/25 5:50 PM, Gao Xiang wrote:

> Could you confirm how docker/containerd or podman parses such image?

I confirm that images with such layers work well at least in containerd 
with overlayfs. We encounter problems during experiments with containerd 
and erofs. Also, GNU tar and BSD tar are good without end-of-archive zeros.

> 
> Because the POSIX standard says:
> https://pubs.opengroup.org/onlinepubs/9699919799/utilities/pax.html
> "At the end of the archive file there shall be two 512-byte blocks filled
> with binary zeros, interpreted as an end-of-archive indicator."
> 
> So such tar layers will be non-standard, I wonder we need at least
> a erofs_warn() message for such tars at least.
> 

Good point. I think I can add erofs_warn() message to the patch.


P.S. I've noticed an interesting detail after submitting the patch. 
Produced erofs image reports an enormous file size after conversion error:

$ mkfs.erofs --tar=f --aufs --quiet -Enoinline_data test.erofs 
test-no-end.tar
-rw-r--r--    1 user  admin  2199023255552 Sep 29 13:43 test.erofs
$ du -sh test.erofs
4,0K    test.erofs

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