Struct OverlayProvider 

pub struct OverlayProvider;

Overlayfs provider — near-instant CoW mounts (Linux only).

Layout:

cache_dir/           ← lower (read-only, shared across boxes)
box_dir/upper/       ← upper (per-box writes)
box_dir/work/        ← overlayfs workdir
box_dir/merged/      ← merged view → RootfsSource::Directory

Trait Implementations

impl RootfsProvider for OverlayProvider

fn prepare(&self, box_dir: &Path, cache_dir: &Path) -> Result<PathBuf>

Prepare a rootfs at box_dir from the cached read-only layer at cache_dir.

fn cleanup(&self, box_dir: &Path, persistent: bool) -> Result<()>

Cleanup after box stops.

fn name(&self) -> &'static str

Human-readable name for logging.

fn resume_for_boot( &self, box_dir: &Path, options: RootfsResumeOptions, ) -> Result<Option<ResumedRootfs>>

Reopen a durable guest-owned generation without reconstructing a host staging tree. Directory providers return None.

fn prepare_oci_for_boot( &self, box_dir: &Path, options: RootfsOciPrepareOptions<'_>, ) -> Result<Option<ResumedRootfs>>

Build a rootfs artifact directly from verified OCI layers. Providers that require a directory staging view return None and retain the compatibility preparation flow.

fn prepare_empty(&self, box_dir: &Path) -> Result<PathBuf>

Prepare an empty writable rootfs for an OCI cache miss.

fn finalize_for_boot( &self, box_dir: &Path, staged_rootfs: &Path, options: RootfsFinalizeOptions, ) -> Result<RootfsSource>

Finalize the staged tree and choose the root filesystem transport.

fn preserve_on_boot_failure(&self, box_dir: &Path) -> bool

Whether a failed boot must retain the provider’s rootfs generations.

fn record_clean_stop(&self, box_dir: &Path) -> Result<()>

Record that a guest-owned rootfs completed a verified clean stop.

fn supports_artifact_cache(&self) -> bool

Whether this provider can consume the immutable artifact cache contract.

fn supports_direct_oci_assembly(&self) -> bool

Whether layout preparation should offer verified OCI inputs before allocating a directory staging transport.

fn guest_owns_terminal_fencing(&self) -> bool

Whether guest-init, rather than the host staging view, owns terminal metadata invalidation for this provider’s supported lifecycle modes.

fn guest_owns_diff_baseline(&self) -> bool

Whether guest-init must capture the pristine diff baseline because the finalized rootfs has no host-visible directory.