pub trait Ext4BlockdevIface {
// Required methods
fn phys_block_size(&mut self) -> u32;
fn phys_block_count(&mut self) -> u64;
fn open(&mut self) -> Result<()>;
fn close(&mut self) -> Result<()>;
fn read(&mut self, buf: *mut u8, block: u64, bcount: u32) -> Result<u32>;
fn write(&mut self, buf: *const u8, block: u64, bcount: u32) -> Result<u32>;
fn lock(&self) -> Result<()>;
fn unlock(&self) -> Result<()>;
}