Struct OwnedRwSlice 

pub struct OwnedRwSlice { /* private fields */ }

Owned, read-WRITE slice over an Arc<dyn BlockDevice>. Use when the parent is writable and the slice should propagate writes (e.g. an individual partition handed to a filesystem driver).

Reads outside [0, length) return Error::ShortRead with got: 0; writes outside it return Error::OutOfBounds. The two directions differ on purpose — see the module docs.

Implementations

impl OwnedRwSlice

pub fn new(parent: Arc<dyn BlockDevice>, start: u64, length: u64) -> Self

length is clamped to what the parent can back, so size_bytes() never exceeds it and a write past the parent’s end is Error::OutOfBounds from this slice rather than whatever the parent makes of an address beyond itself. See window_on_parent.

pub fn start(&self) -> u64

Byte offset of this slice on the parent device.

pub fn length(&self) -> u64

Length of this slice in bytes (== size_bytes()).

Trait Implementations

impl BlockDevice for OwnedRwSlice

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

Range first, writability second: a write that is both out of range and aimed at a read-only parent reports Error::OutOfBounds, not Error::ReadOnly. The range is a property of this slice and is knowable without asking the parent anything, so it is the more specific of the two answers.

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

Flush pending writes to stable storage. No-op by default.

fn is_writable(&self) -> bool

Whether write_at is likely to succeed. Mount paths use this to decide whether to attempt journal replay or stay strict-read-only.

fn set_len(&self, _new_len: u64) -> Result<()>

Set the device’s length to new_len. Default: returns Error::ReadOnly.

fn can_grow(&self) -> bool

Whether set_len is likely to succeed. Default: false.

impl BlockRead for OwnedRwSlice

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

Read exactly buf.len() bytes starting at offset (bytes from the start of the device).

fn size_bytes(&self) -> u64

Total device size in bytes. Used for bounds checks.