common: abort load on ENOSPC and output clear error

[zvenigorodsky]

Fix: containers/podman#26197

When loading images, exit archive checks when receiving ENOSPC error, and display a clearer exit message for the user.

tests for podman at: containers/podman#27374

[podmanbot]

✅ A new PR has been created in buildah to vendor these changes: containers/buildah#6452

[zvenigorodsky]

Hey, I saw the issue containers/podman#26197 is stale, and decided to look into it.

Looked at zhengkezhou1's PR and researched about fmt.Errorf.

It does implement the unwrap method on the error (https://pkg.go.dev/fmt#Errorf) , and errors.Is does call the unwrap on fmt.Errorf (https://pkg.go.dev/errors#Is)

[zvenigorodsky]

Tested this by creating a mounted filesystem with minimal storage and pointed store.graphroot to said filesystem,
works as intended

[Luap99]

Thanks for the PR.

As I noted on containers/common#2446 (review) I don't think this can work because the chroot extraction and thus ENOSPC can happen in a subprocess so the error is just a string not the actual ENOSPC object so this cannot match I believe.

Can you provide the full reproducer you used to test this patch?

[Luap99]

please do do that, that throws away the full error context, i.e. you don't even know which file was attempted to write.

This must still return err.

[mtrmac]

can happen in a subprocess

(Note that this is platform-specific; testing on macOS or Windows would not show this.)

[zvenigorodsky]

I forgot about other platforms, I tested this on a fedora 41 by creating a filesystem with minimal storage and pointing graphroot to the filesystem with a config file.

Here's a bash script that basically reproduces the setting:

#!/bin/bash

USER=$(whoami)

dd if=/dev/zero of=temp_storage bs=1M count=128
mkfs -t ext4 temp_storage
mkdir temp_storage_fs

sudo mount temp_storage temp_storage_fs
sudo chown $USER:$USER temp_storage_fs

cat > custom.conf <<EOF
[storage]
graphroot="$PWD/temp_storage_fs"
EOF

go mod edit -replace go.podman.io/common=github.com/zvenigorodsky/container-libs/common@main

go mod tidy

go mod vendor

make bin/podman 

# You can replace with any image that will be larger than 128Mb
HEAVY_IMAGE=quay.io/openshift-release-dev/ocp-release:4.20.2-ppc64le

./bin/podman pull $HEAVY_IMAGE 

./bin/podman save $HEAVY_IMAGE -o image.tar

export CONTAINERS_STORAGE_CONF="$PWD/custom.conf" 

./bin/podman load -i image.tar

[mtrmac]

That’s just guessing, and discarding the original cause.

[mtrmac]

This is still discarding the original error value [maybe we would want to modify the text, but it is still valuable to retain the regional error so that errors.As works higher in the stack], and not handling chrootarchive; both from the very first #419 (comment) .

[Luap99]

Note that I couldn't get go mod edit -replace go.podman.io/containers/common=github.com/zvenigorodsky/container-libs/common to work, it looked like container-libs/common is still not a drop-in replacement to containers/common (correct me if I'm wrong).

It works fine, after all we already use the monorepo in podman. It is your command which is wrong. The module name is go.podman.io/common (no containers)

https://github.com/containers/container-libs/blob/main/CONTRIBUTING_GO.md#testing-changes-in-a-dependent-repository

[zvenigorodsky]

... and not handling chrootarchive; ...

Could you guide me in how can I test this for other platforms?