Struct Slot 

pub struct Slot {
    pub file: RegularFile,
    pub fba: FileBlockNumber,
    pub page: Page,
    pub writeback_size: Option<usize>,
}

A single entry in the page cache.

A Slot corresponds to one file block stored in memory.

Fields

file: RegularFile

The file this slot belongs to.

fba: FileBlockNumber

The file block number this slot represents.

page: Page

The backing page containing the block’s data.

writeback_size: Option<usize>

Size to be write-backed if dirtied. If the slot is clean, this will be None.

Implementations

impl Slot

pub fn new(file: RegularFile, fba: FileBlockNumber, page: Page) -> Self

Create a new slot for the given file, block, and backing page.

By default, the slot is clean (i.e., writeback_size is None).

pub fn read_page(&self, buf: &mut [u8; 4096])

Copy the page contents into the provided buffer.

The buffer must be exactly 4096 bytes long, representing a full page. This method does not trigger I/O.

pub fn write_page(&mut self, buf: &[u8; 4096], min_size: usize)

Update the page contents from the provided buffer.

Marks the slot as dirty with a write-back of at least min_size bytes. The buffer must be exactly 4096 bytes long.

pub fn writeback(&mut self) -> Result<(), KernelError>

Write back the dirty portion of the page to the underlying file.

• If writeback_size is Some(size), representing slot is dirty, marked with the desired minimum file size (in bytes) after write-back.
• On success, clears the writeback_size to None.

If the slot is clean, this does not trigger the I/O.

Trait Implementations

impl Drop for Slot

fn drop(&mut self)

Executes the destructor for this type.