feat: Add concept for DeviceCaps & BlockCaps

foyer-storage/src/engine/block/engine.rs

@@ -59,7 +59,7 @@ use crate::{
     },
     error::{Error, Result},
     filter::conditions::IoThrottle,
-    io::{bytes::IoSliceMut, PAGE},
+    io::{bytes::IoSliceMut, device::DeviceCaps, PAGE},
     keeper::PieceRef,
     runtime::Runtime,
     serde::EntryDeserializer,
@@ -332,6 +332,10 @@ where
         let device = self.device;
         let block_size = self.block_size;
 
+        match device.caps() {
+            DeviceCaps::Block(_) => {}
+        }
+
         let mut tombstones = vec![];
 
         let tombstone_log = if self.enable_tombstone_log {

foyer-storage/src/io/device/combined.rs

@@ -16,7 +16,7 @@ use std::sync::{Arc, RwLock};
 
 use crate::{
     io::{
-        device::{Device, DeviceBuilder, Partition, PartitionId},
+        device::{BlockCaps, Device, DeviceBuilder, DeviceCaps, Partition, PartitionId},
         error::{IoError, IoResult},
     },
     RawFile, Statistics, Throttle,
@@ -65,13 +65,24 @@ impl CombinedDeviceBuilder {
 
 impl DeviceBuilder for CombinedDeviceBuilder {
     fn build(self) -> IoResult<Arc<dyn Device>> {
+        let mut alignment = 0;
+        for device in &self.devices {
+            match device.caps() {
+                DeviceCaps::Block(block) => alignment = alignment.max(block.alignment),
+            }
+        }
+        if self.devices.is_empty() {
+            return Err(IoError::other("combined device requires at least one inner device"));
+        }
+
         let device = CombinedDevice {
             devices: self.devices,
             statistics: Arc::new(Statistics::new(self.throttle)),
             inner: RwLock::new(Inner {
                 partitions: vec![],
                 next: 0,
             }),
+            caps: DeviceCaps::Block(BlockCaps { alignment }),
         };
         let device = Arc::new(device);
         Ok(device)
@@ -90,9 +101,14 @@ pub struct CombinedDevice {
     devices: Vec<Arc<dyn Device>>,
     inner: RwLock<Inner>,
     statistics: Arc<Statistics>,
+    caps: DeviceCaps,
 }
 
 impl Device for CombinedDevice {
+    fn caps(&self) -> &DeviceCaps {
+        &self.caps
+    }
+
     fn capacity(&self) -> usize {
         self.devices.iter().map(|d| d.capacity()).sum()
     }

foyer-storage/src/io/device/file.rs

@@ -22,7 +22,10 @@ use fs4::free_space;
 
 use crate::{
     io::{
-        device::{statistics::Statistics, throttle::Throttle, Device, DeviceBuilder, Partition, PartitionId},
+        device::{
+            statistics::Statistics, throttle::Throttle, BlockCaps, Device, DeviceBuilder, DeviceCaps, Partition,
+            PartitionId,
+        },
         error::IoResult,
         PAGE,
     },
@@ -119,6 +122,7 @@ impl DeviceBuilder for FileDeviceBuilder {
             capacity,
             statistics,
             partitions: RwLock::new(vec![]),
+            caps: DeviceCaps::Block(BlockCaps::default()),
         };
         let device: Arc<dyn Device> = Arc::new(device);
         Ok(device)
@@ -132,9 +136,14 @@ pub struct FileDevice {
     capacity: usize,
     partitions: RwLock<Vec<Arc<FilePartition>>>,
     statistics: Arc<Statistics>,
+    caps: DeviceCaps,
 }
 
 impl Device for FileDevice {
+    fn caps(&self) -> &DeviceCaps {
+        &self.caps
+    }
+
     fn capacity(&self) -> usize {
         self.capacity
     }

foyer-storage/src/io/device/fs.rs

@@ -22,7 +22,10 @@ use fs4::free_space;
 
 use crate::{
     io::{
-        device::{statistics::Statistics, throttle::Throttle, Device, DeviceBuilder, Partition, PartitionId},
+        device::{
+            statistics::Statistics, throttle::Throttle, BlockCaps, Device, DeviceBuilder, DeviceCaps, Partition,
+            PartitionId,
+        },
         error::IoResult,
         PAGE,
     },
@@ -103,6 +106,7 @@ impl DeviceBuilder for FsDeviceBuilder {
             #[cfg(target_os = "linux")]
             direct: self.direct,
             partitions: RwLock::new(vec![]),
+            caps: DeviceCaps::Block(BlockCaps::default()),
         };
         let device: Arc<dyn Device> = Arc::new(device);
         Ok(device)
@@ -118,6 +122,7 @@ pub struct FsDevice {
     #[cfg(target_os = "linux")]
     direct: bool,
     partitions: RwLock<Vec<Arc<FsPartition>>>,
+    caps: DeviceCaps,
 }
 
 impl FsDevice {
@@ -128,6 +133,10 @@ impl FsDevice {
 }
 
 impl Device for FsDevice {
+    fn caps(&self) -> &DeviceCaps {
+        &self.caps
+    }
+
     fn capacity(&self) -> usize {
         self.capacity
     }

foyer-storage/src/io/device/mod.rs

@@ -17,7 +17,7 @@ pub mod throttle;
 
 use std::{any::Any, fmt::Debug, sync::Arc};
 
-use crate::io::{device::statistics::Statistics, error::IoResult};
+use crate::io::{device::statistics::Statistics, error::IoResult, PAGE};
 
 pub type PartitionId = u32;
 
@@ -42,6 +42,26 @@ pub trait DeviceBuilder: Send + Sync + 'static + Debug {
     fn build(self) -> IoResult<Arc<dyn Device>>;
 }
 
+/// The capabilities of a device.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum DeviceCaps {
+    /// A block-addressable device.
+    Block(BlockCaps),
+}
+
+/// Capabilities for block devices.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct BlockCaps {
+    /// The required alignment for block I/O.
+    pub alignment: usize,
+}
+
+impl Default for BlockCaps {
+    fn default() -> Self {
+        Self { alignment: PAGE }
+    }
+}
+
 /// Partition is a logical segment of a device.
 pub trait Partition: Send + Sync + 'static + Debug + Any {
     /// Get the id of the partition.
@@ -61,6 +81,9 @@ pub trait Partition: Send + Sync + 'static + Debug + Any {
 
 /// Device trait.
 pub trait Device: Send + Sync + 'static + Debug + Any {
+    /// Get the capabilities of the device.
+    fn caps(&self) -> &DeviceCaps;
+
     /// Get the capacity of the device.
     ///
     /// NOTE: `capacity` must be 4K aligned.

foyer-storage/src/io/device/noop.rs

@@ -16,7 +16,10 @@ use std::sync::{Arc, RwLock};
 
 use crate::{
     io::{
-        device::{statistics::Statistics, throttle::Throttle, Device, DeviceBuilder, Partition, PartitionId},
+        device::{
+            statistics::Statistics, throttle::Throttle, BlockCaps, Device, DeviceBuilder, DeviceCaps, Partition,
+            PartitionId,
+        },
         error::IoResult,
     },
     RawFile,
@@ -48,6 +51,7 @@ impl DeviceBuilder for NoopDeviceBuilder {
             partitions: RwLock::new(vec![]),
             capacity: self.capacity,
             statistics,
+            caps: DeviceCaps::Block(BlockCaps::default()),
         }))
     }
 }
@@ -59,9 +63,14 @@ pub struct NoopDevice {
     capacity: usize,
 
     statistics: Arc<Statistics>,
+    caps: DeviceCaps,
 }
 
 impl Device for NoopDevice {
+    fn caps(&self) -> &DeviceCaps {
+        &self.caps
+    }
+
     fn capacity(&self) -> usize {
         self.capacity
     }

foyer-storage/src/io/device/partial.rs

@@ -16,7 +16,7 @@ use std::sync::{Arc, RwLock};
 
 use crate::{
     io::{
-        device::{statistics::Statistics, Device, DeviceBuilder, Partition, PartitionId},
+        device::{statistics::Statistics, Device, DeviceBuilder, DeviceCaps, Partition, PartitionId},
         error::IoResult,
     },
     IoError,
@@ -51,10 +51,14 @@ impl PartialDeviceBuilder {
 
 impl DeviceBuilder for PartialDeviceBuilder {
     fn build(self) -> IoResult<Arc<dyn Device>> {
+        let caps = match self.device.caps() {
+            DeviceCaps::Block(block) => *block,
+        };
         Ok(Arc::new(PartialDevice {
             inner: self.device,
             capacity: self.capacity,
             partitions: RwLock::new(vec![]),
+            caps: DeviceCaps::Block(caps),
         }))
     }
 }
@@ -65,9 +69,14 @@ pub struct PartialDevice {
     inner: Arc<dyn Device>,
     capacity: usize,
     partitions: RwLock<Vec<Arc<PartialPartition>>>,
+    caps: DeviceCaps,
 }
 
 impl Device for PartialDevice {
+    fn caps(&self) -> &DeviceCaps {
+        &self.caps
+    }
+
     fn capacity(&self) -> usize {
         self.capacity
     }

foyer-storage/src/prelude.rs

@@ -38,7 +38,7 @@ pub use crate::{
             partial::PartialDeviceBuilder,
             statistics::Statistics,
             throttle::{IopsCounter, Throttle},
-            Device, DeviceBuilder, RawFile,
+            BlockCaps, Device, DeviceBuilder, DeviceCaps, RawFile,
         },
         engine::{
             noop::{NoopIoEngine, NoopIoEngineBuilder},