vmm: disk resize infrastructure

Add basic infrastructure so resize events are
propagated to the underlying disk implementation.

On-behalf-of: SAP thomas.prescher@sap.com
Signed-off-by: Thomas Prescher <thomas.prescher@cyberus-technology.de>

vmm/src/api/mod.rs

@@ -315,6 +315,8 @@ pub trait RequestHandler {
 
     fn vm_resize_zone(&mut self, id: String, desired_ram: u64) -> Result<(), VmError>;
 
+    fn vm_resize_disk(&mut self, id: String, desired_size: u64) -> Result<(), VmError>;
+
     fn vm_add_device(&mut self, device_cfg: DeviceConfig) -> Result<Option<Vec<u8>>, VmError>;
 
     fn vm_add_user_device(

vmm/src/device_manager.rs

@@ -670,6 +670,10 @@ pub enum DeviceManagerError {
     /// Error adding fw_cfg to bus.
     #[error("Error adding fw_cfg to bus")]
     ErrorAddingFwCfgToBus(#[source] vm_device::BusError),
+
+    /// Disk resizing failed.
+    #[error("Disk resize error")]
+    DiskResize(#[source] virtio_devices::block::Error),
 }
 
 pub type DeviceManagerResult<T> = result::Result<T, DeviceManagerError>;
@@ -4901,6 +4905,18 @@ impl DeviceManager {
         0
     }
 
+    pub fn resize_disk(&mut self, device_id: &str, new_size: u64) -> DeviceManagerResult<()> {
+        for dev in &self.block_devices {
+            let mut disk = dev.lock().unwrap();
+            if disk.id() == device_id {
+                return disk
+                    .resize(new_size)
+                    .map_err(DeviceManagerError::DiskResize);
+            }
+        }
+        Err(DeviceManagerError::UnknownDeviceId(device_id.to_string()))
+    }
+
     pub fn device_tree(&self) -> Arc<Mutex<DeviceTree>> {
         self.device_tree.clone()
     }

vmm/src/lib.rs

@@ -1962,6 +1962,16 @@ impl RequestHandler for Vmm {
         }
     }
 
+    fn vm_resize_disk(&mut self, id: String, desired_size: u64) -> result::Result<(), VmError> {
+        self.vm_config.as_ref().ok_or(VmError::VmNotCreated)?;
+
+        if let Some(ref mut vm) = self.vm {
+            return vm.resize_disk(&id, desired_size);
+        }
+
+        Err(VmError::ResizeDisk)
+    }
+
     fn vm_resize_zone(&mut self, id: String, desired_ram: u64) -> result::Result<(), VmError> {
         self.vm_config.as_ref().ok_or(VmError::VmNotCreated)?;
 

vmm/src/vm.rs

@@ -246,6 +246,9 @@ pub enum Error {
     #[error("Failed resizing a memory zone")]
     ResizeZone,
 
+    #[error("Failed resizing a disk image")]
+    ResizeDisk,
+
     #[error("Cannot activate virtio devices")]
     ActivateVirtioDevices(#[source] DeviceManagerError),
 
@@ -1706,6 +1709,16 @@ impl Vm {
         Ok(())
     }
 
+    pub fn resize_disk(&mut self, id: &str, desired_size: u64) -> Result<()> {
+        self.device_manager
+            .lock()
+            .unwrap()
+            .resize_disk(id, desired_size)
+            .map_err(Error::DeviceManager)?;
+
+        Ok(())
+    }
+
     pub fn resize_zone(&mut self, id: &str, desired_memory: u64) -> Result<()> {
         let memory_config = &mut self.config.lock().unwrap().memory;