Allow specifying a custom devmapper snapshot device on snapshot boot

src/devices/src/virtio/block/persist.rs

@@ -57,7 +57,7 @@ pub struct BlockState {
     )]
     cache_type: CacheTypeState,
     root_device: bool,
-    disk_path: String,
+    pub disk_path: String,
     virtio_state: VirtioDeviceState,
     rate_limiter_state: RateLimiterState,
 }

src/vmm/src/device_manager/persist.rs

@@ -239,11 +239,12 @@ impl<'a> Persist<'a> for MMIODeviceManager {
 
                     // Send Transport event to reset connections if device
                     // is activated.
-                    if vsock.is_activated() {
+                    // TODO: temporarily disabled to avoid FC agent becoming unavailable when restoring snapshots
+                    /*if vsock.is_activated() {
                         vsock.send_transport_reset_event().unwrap_or_else(|e| {
                             error!("Failed to send reset transport event: {:?}", e);
                         });
-                    }
+                    }*/
 
                     states.vsock_device = Some(ConnectedVsockState {
                         device_id: devid.clone(),

src/vmm/src/persist.rs

@@ -418,7 +418,18 @@ pub fn restore_from_snapshot(
 ) -> std::result::Result<Arc<Mutex<Vmm>>, LoadSnapshotError> {
     use self::LoadSnapshotError::*;
     let track_dirty_pages = params.enable_diff_snapshots;
-    let microvm_state = snapshot_state_from_file(&params.snapshot_path, version_map)?;
+    let mut microvm_state = snapshot_state_from_file(&params.snapshot_path, version_map)?;
+
+    let new_snapshot_path = &params.new_snapshot_path;
+
+    if ! new_snapshot_path.eq("") {
+        let n = microvm_state.device_states.block_devices.len();
+        for i in 0..n {
+            if microvm_state.device_states.block_devices[i].device_state.disk_path.contains("thinpool-snap") {
+                microvm_state.device_states.block_devices[i].device_state.disk_path = new_snapshot_path.clone();
+            }
+        }
+    }
 
     // Some sanity checks before building the microvm.
     snapshot_state_sanity_check(&microvm_state)?;

src/vmm/src/vmm_config/snapshot.rs

@@ -50,6 +50,8 @@ pub struct LoadSnapshotParams {
     pub mem_file_path: PathBuf,
     /// Setting this flag enables user page faults handling by a different process.
     pub enable_user_page_faults: bool,
+    /// Setting this string to nonempty changes the snapshot device
+    pub new_snapshot_path: String,
     /// Path to the passfd socket.
     pub sock_file_path: PathBuf,
     /// Setting this flag will enable KVM dirty page tracking and will

tools/devtool

@@ -69,11 +69,11 @@
 #     would help with reproducible builds (in addition to pinning Cargo.lock)
 
 # Development container image (without tag)
-DEVCTR_IMAGE_NO_TAG="docker.io/vhiveease/fcuvm_dev"
+DEVCTR_IMAGE_NO_TAG="docker.io/amohoste/fcuvm_dev"
 
 # Development container tag
-#DEVCTR_IMAGE_TAG="v30"
-DEVCTR_IMAGE_TAG="v16_upf"
+DEVCTR_IMAGE_TAG="v30"
+#DEVCTR_IMAGE_TAG="v16_upf"
 
 # Development container image (name:tag)
 # This should be updated whenever we upgrade the development container.