Struct BlockBitmap 

#[repr(C, packed(1))]
pub struct BlockBitmap {
    bits: [u64; 512],
}

Represents the on-disk block allocation bitmap for the file system.

Each bit in the BlockBitmap corresponds to a single block on disk. A bit value of 1 indicates that the block is in use, while 0 means the block is free and available for allocation.

Fields

bits: [u64; 512]

Implementations

impl BlockBitmap

pub fn is_allocated(&self, pos: usize) -> bool

Checks whether a block at the given position is allocated.

Parameters

• pos: The index of the block to check.

Returns

• true if the block is currently marked as allocated (bit is 1).
• false if the block is free (bit is 0).

This method is used to determine the allocation status of a block in the file system’s block bitmap.

pub fn try_allocate(&mut self, pos: usize) -> bool

Attempts to allocate a block at the given position.

Parameters

• pos: The index of the block to allocate.

Returns

• true if the block was previously free and is now marked as allocated.
• false if the block was already allocated (no change).

This method is used during block allocation to claim a free block. If the block is already allocated, it fails without modifying the bitmap.

pub fn deallocate(&mut self, pos: usize) -> bool

deallocate a block at the given position.

Parameters

• pos: The index of the block to deallocate.

Returns

• true if the block was previously free and is now marked as allocated.
• false if the block was already allocated (no change).

This method is used during block allocation to claim a free block. If the block is already allocated, it fails without modifying the bitmap.

Trait Implementations

impl Default for BlockBitmap

fn default() -> Self

Returns the “default value” for a type.

impl MetaData for BlockBitmap

fn load( ffs: &FastFileSystemInner, lba: LogicalBlockAddress, ) -> Result<BlockPointsTo<Self>, KernelError>

Loads a metadata structure from disk at the specified logical block address.