Struct SyncFileBackend 

pub struct SyncFileBackend { /* private fields */ }

Synchronous file-backed BlockBackend — opens the host file once and serializes I/O through a parking_lot::Mutex<File>. The mutex guard is released before the device thread re-acquires its own state lock so the bus is not blocked across host I/O.

The workspace disallowed-types lint pushes runtime I/O onto Tokio; the sync engine is the explicit blocking-I/O alternative for low-IOPS workloads (per 14-virtio-and-devices.md § 4.1) so the std::fs::File allow is intentional. The async engine uses tokio::task::spawn_blocking and lives in a follow-up.

Implementations

impl SyncFileBackend

pub fn open(path: &Path, read_only: bool) -> Result<Self>

Open path for sync I/O.

Errors

std::io::Error if the file cannot be opened.

Trait Implementations

impl BlockBackend for SyncFileBackend

fn size_bytes(&self) -> u64

Total size of the backing storage in bytes.

fn read_at(&self, byte_offset: u64, buf: &mut [u8]) -> Result<()>

Read buf.len() bytes starting at byte_offset.

fn write_at(&self, byte_offset: u64, buf: &[u8]) -> Result<()>

Write buf.len() bytes starting at byte_offset.

fn flush(&self) -> Result<()>

Synchronous flush (fsync).

fn read_only(&self) -> bool

true if the backing storage is opened read-only.

impl Debug for SyncFileBackend

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.