[Bug] xattrs cannot be disabled on layers with volume mounts

[sondavidb]

Description

There's a bug in containerd/continuity#244 where CopyDir() fails on filesystems without xattrs. The syscall to list xattrs will fail with ENOTSUP, and continuity will treat it as a regular error and say it failed. When creating a container, if there are volumes to mount, nerdctl will make a call to this CopyDir() function. This is a problem for us, since by default we disable xattrs unless whiteout directories or file xattrs are detected.

For now we can have xattrs be on by default and allow this change to be opted into, but we should either wait for the upstream bug fix (which could take a long time) or find a somewhat elegant workaround in SOCI.

Steps to reproduce the bug

1. Pull image with a layer that has a volume mount without whiteout dirs or xattrs. (ARM64 for rabbitmq@sha256:19e69a7a65fa6b1d0a5c658bad8ec03d2c9900a98ebbc744c34d49179ff517bf worked for this.)
2. Create SOCI index with xattrs optimization enabled.
3. Push to registry
4. Pull from registry with SOCI and attempt to run container

Describe the results you expected

Container should run instead of erroring with "operation not supported"

Host information

1. OS: Linux
2. Snapshotter Version: v0.6.1
3. Containerd Version: v1.7.18

Any additional context or information about the bug

No response