vmm: Add ability to add virtio-fs device post-boot

Adds DeviceManager method `make_virtio_fs_device` which creates a single
device, and modifies `make_virtio_fs_devices` to use this method.

Implements the new `vm.add-fs route`.

Signed-off-by: Dean Sheather <dean@coder.com>

vmm/src/api/http_endpoint.rs

@@ -5,11 +5,11 @@
 
 use crate::api::http::EndpointHandler;
 use crate::api::{
-    vm_add_device, vm_add_disk, vm_add_net, vm_add_pmem, vm_boot, vm_create, vm_delete, vm_info,
-    vm_pause, vm_reboot, vm_remove_device, vm_resize, vm_restore, vm_resume, vm_shutdown,
+    vm_add_device, vm_add_disk, vm_add_fs, vm_add_net, vm_add_pmem, vm_boot, vm_create, vm_delete,
+    vm_info, vm_pause, vm_reboot, vm_remove_device, vm_resize, vm_restore, vm_resume, vm_shutdown,
     vm_snapshot, vmm_ping, vmm_shutdown, ApiError, ApiRequest, ApiResult, DeviceConfig, DiskConfig,
-    NetConfig, PmemConfig, RestoreConfig, VmAction, VmConfig, VmRemoveDeviceData, VmResizeData,
-    VmSnapshotConfig,
+    FsConfig, NetConfig, PmemConfig, RestoreConfig, VmAction, VmConfig, VmRemoveDeviceData,
+    VmResizeData, VmSnapshotConfig,
 };
 use micro_http::{Body, Method, Request, Response, StatusCode, Version};
 use serde_json::Error as SerdeError;
@@ -71,6 +71,9 @@ pub enum HttpError {
     /// Could not add a disk to a VM
     VmAddDisk(ApiError),
 
+    /// Could not add a fs to a VM
+    VmAddFs(ApiError),
+
     /// Could not add a pmem device to a VM
     VmAddPmem(ApiError),
 
@@ -494,12 +497,33 @@ impl EndpointHandler for VmAddFs {
     fn handle_request(
         &self,
         req: &Request,
-        _api_notifier: EventFd,
-        _api_sender: Sender<ApiRequest>,
+        api_notifier: EventFd,
+        api_sender: Sender<ApiRequest>,
     ) -> Response {
         match req.method() {
-            // Not implemented.
-            Method::Put => Response::new(Version::Http11, StatusCode::NotImplemented),
+            Method::Put => {
+                match &req.body {
+                    Some(body) => {
+                        // Deserialize into a FsConfig
+                        let vm_add_fs_data: FsConfig = match serde_json::from_slice(body.raw())
+                            .map_err(HttpError::SerdeJsonDeserialize)
+                        {
+                            Ok(config) => config,
+                            Err(e) => return error_response(e, StatusCode::BadRequest),
+                        };
+
+                        // Call vm_add_fs()
+                        match vm_add_fs(api_notifier, api_sender, Arc::new(vm_add_fs_data))
+                            .map_err(HttpError::VmAddFs)
+                        {
+                            Ok(_) => Response::new(Version::Http11, StatusCode::NoContent),
+                            Err(e) => error_response(e, StatusCode::InternalServerError),
+                        }
+                    }
+
+                    None => Response::new(Version::Http11, StatusCode::BadRequest),
+                }
+            }
             _ => Response::new(Version::Http11, StatusCode::BadRequest),
         }
     }

vmm/src/api/mod.rs

@@ -37,7 +37,9 @@ pub use self::http::start_http_thread;
 pub mod http;
 pub mod http_endpoint;
 
-use crate::config::{DeviceConfig, DiskConfig, NetConfig, PmemConfig, RestoreConfig, VmConfig};
+use crate::config::{
+    DeviceConfig, DiskConfig, FsConfig, NetConfig, PmemConfig, RestoreConfig, VmConfig,
+};
 use crate::vm::{Error as VmError, VmState};
 use std::io;
 use std::sync::mpsc::{channel, RecvError, SendError, Sender};
@@ -122,6 +124,9 @@ pub enum ApiError {
     /// The disk could not be added to the VM.
     VmAddDisk(VmError),
 
+    /// The fs could not be added to the VM.
+    VmAddFs(VmError),
+
     /// The pmem device could not be added to the VM.
     VmAddPmem(VmError),
 
@@ -230,6 +235,9 @@ pub enum ApiRequest {
     /// Add a disk to the VM.
     VmAddDisk(Arc<DiskConfig>, Sender<ApiResponse>),
 
+    /// Add a fs to the VM.
+    VmAddFs(Arc<FsConfig>, Sender<ApiResponse>),
+
     /// Add a pmem device to the VM.
     VmAddPmem(Arc<PmemConfig>, Sender<ApiResponse>),
 
@@ -484,6 +492,24 @@ pub fn vm_add_disk(
     Ok(())
 }
 
+pub fn vm_add_fs(
+    api_evt: EventFd,
+    api_sender: Sender<ApiRequest>,
+    data: Arc<FsConfig>,
+) -> ApiResult<()> {
+    let (response_sender, response_receiver) = channel();
+
+    // Send the VM add-fs request.
+    api_sender
+        .send(ApiRequest::VmAddFs(data, response_sender))
+        .map_err(ApiError::RequestSend)?;
+    api_evt.write(1).map_err(ApiError::EventFdWrite)?;
+
+    response_receiver.recv().map_err(ApiError::ResponseRecv)??;
+
+    Ok(())
+}
+
 pub fn vm_add_pmem(
     api_evt: EventFd,
     api_sender: Sender<ApiRequest>,