Struct CacheBlockStorage 

pub struct CacheBlockStorage<D, H, B, HD, IO> { /* private fields */ }

Canonical physical-resource state machine for one cache block.

D, H, and B are backend-owned device, host, and backing resources. HD and IO are backend-owned exact completions. Private resource slots prevent a backend from constructing contradictory phase/resource states.

Implementations

impl<D, H, B, HD, IO> CacheBlockStorage<D, H, B, HD, IO>

pub fn device(id: CacheBlockId, device: D, backing: Option<B>) -> Self

Creates device residency, optionally retaining an existing backing.

pub fn host(id: CacheBlockId, host: H, backing: Option<B>) -> Self

Creates host residency, optionally retaining an existing backing.

pub fn disk(id: CacheBlockId, backing: B) -> Self

Creates ready backing-only residency.

pub const fn phase(&self) -> CacheStoragePhase

Current canonical phase.

pub const fn id(&self) -> &CacheBlockId

Block whose physical resources are owned by this state machine.

pub const fn tier(&self) -> CacheTier

Current logical accounting tier.

pub fn device_resource(&self) -> Option<&D>

Backend device resources, including while a demotion is pending.

pub fn host_resource(&self) -> Option<&H>

Backend host resources.

pub fn backing(&self) -> Option<&B>

Durable backing retained by the current phase.

pub fn host_demotion(&self) -> Option<&HD>

Exact pending host-demotion completion.

pub fn io(&self) -> Option<&IO>

Exact pending backing-store completion.

impl<D, H, B, HD: CacheHostDemotionOperation, IO: CacheIoOperation> CacheBlockStorage<D, H, B, HD, IO>

pub fn io_matches(&self, key: &CacheIoOperationKey) -> bool

Returns whether the exact backing-store operation is pending.

pub fn fail_io_if_matches(&mut self, key: &CacheIoOperationKey) -> bool

Fails the operation only when the exact key is still pending.

pub fn begin_host_demotion( &mut self, operation: HD, ) -> Result<(), CacheStorageError>

Begins an exact device-to-host transition while retaining device state.

pub fn finish_host_demotion( &mut self, operation_id: u64, host: H, ) -> Result<(D, HD), CacheStorageError>

Commits the matching host demotion and returns released device resources.

pub fn fail_host_demotion( &mut self, operation_id: u64, ) -> Result<HD, CacheStorageError>

Abandons the matching host demotion and restores device residency.

pub fn release_device_to_disk(&mut self) -> Result<D, CacheStorageError>

Releases backed device resources directly to backing-only residency.

pub fn release_host_to_disk(&mut self) -> Result<H, CacheStorageError>

Releases backed host resources directly to backing-only residency.

pub fn begin_write(&mut self, operation: IO) -> Result<(), CacheStorageError>

Starts the exact write that owns unbacked host resources.

pub fn finish_write( &mut self, key: &CacheIoOperationKey, backing: B, ) -> Result<(H, IO), CacheStorageError>

Commits the matching write and returns released host resources.

pub fn begin_read(&mut self, operation: IO) -> Result<(), CacheStorageError>

Starts the exact read that owns backing-only resources.

pub fn finish_read( &mut self, key: &CacheIoOperationKey, host: H, ) -> Result<IO, CacheStorageError>

Commits the matching read while retaining its durable backing.

pub fn fail_io( &mut self, key: &CacheIoOperationKey, ) -> Result<IO, CacheStorageError>

Cancels or fails the matching I/O and restores its stable source phase.

pub fn promote_host( &mut self, device: D, ) -> Result<CacheHostPromotion<H>, CacheStorageError>

Promotes stable host resources to device residency.

pub fn restore_host( &mut self, promotion: CacheHostPromotion<H>, ) -> Result<D, CacheStorageError>

Restores host resources after a rejected promotion.

Trait Implementations

impl<D: Clone, H: Clone, B: Clone, HD: Clone, IO: Clone> Clone for CacheBlockStorage<D, H, B, HD, IO>

fn clone(&self) -> CacheBlockStorage<D, H, B, HD, IO>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<D: Debug, H: Debug, B: Debug, HD: Debug, IO: Debug> Debug for CacheBlockStorage<D, H, B, HD, IO>

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

Formats the value using the given formatter.