From 4918c1ca7f5799c2ce8b4a0a0b7738350c39287f Mon Sep 17 00:00:00 2001
From: Sebastien Boeuf <sebastien.boeuf@intel.com>
Date: Thu, 12 Aug 2021 00:12:48 +0200
Subject: [PATCH] block_util, vmm: Propagate error on QcowDiskSync creation

Instead of panicking with an expect() function, the QcowDiskSync::new
function now propagates the error properly. This ensures the VMM will
not panic, which might be the source of weird errors if only one thread
exits while the VMM continues to run.

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
---
 block_util/src/qcow_sync.rs | 11 +++++------
 vmm/src/device_manager.rs   |  8 +++++++-
 2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/block_util/src/qcow_sync.rs b/block_util/src/qcow_sync.rs
index 1590f3754..1c5229ed7 100644
--- a/block_util/src/qcow_sync.rs
+++ b/block_util/src/qcow_sync.rs
@@ -4,7 +4,7 @@
 
 use crate::async_io::{AsyncIo, AsyncIoResult, DiskFile, DiskFileResult};
 use crate::{disk_size, fsync_sync, read_vectored_sync, write_vectored_sync};
-use qcow::{QcowFile, RawFile};
+use qcow::{QcowFile, RawFile, Result as QcowResult};
 use std::fs::File;
 use std::sync::{Arc, Mutex};
 use vmm_sys_util::eventfd::EventFd;
@@ -15,12 +15,11 @@ pub struct QcowDiskSync {
 }
 
 impl QcowDiskSync {
-    pub fn new(file: File, direct_io: bool) -> Self {
-        QcowDiskSync {
-            qcow_file: QcowFile::from(RawFile::new(file, direct_io))
-                .expect("Failed creating QcowFile"),
+    pub fn new(file: File, direct_io: bool) -> QcowResult<Self> {
+        Ok(QcowDiskSync {
+            qcow_file: QcowFile::from(RawFile::new(file, direct_io))?,
             semaphore: Arc::new(Mutex::new(())),
-        }
+        })
     }
 }
 
diff --git a/vmm/src/device_manager.rs b/vmm/src/device_manager.rs
index a07dbd79f..9c9fc8a6a 100644
--- a/vmm/src/device_manager.rs
+++ b/vmm/src/device_manager.rs
@@ -417,6 +417,9 @@ pub enum DeviceManagerError {
     /// Failed to create FixedVhdDiskSync
     CreateFixedVhdDiskSync(io::Error),
 
+    /// Failed to create QcowDiskSync
+    CreateQcowDiskSync(qcow::Error),
+
     /// Failed adding DMA mapping handler to virtio-mem device.
     AddDmaMappingHandlerVirtioMem(virtio_devices::mem::Error),
 
@@ -1936,7 +1939,10 @@ impl DeviceManager {
                 }
                 ImageType::Qcow2 => {
                     info!("Using synchronous QCOW disk file");
-                    Box::new(QcowDiskSync::new(file, disk_cfg.direct)) as Box<dyn DiskFile>
+                    Box::new(
+                        QcowDiskSync::new(file, disk_cfg.direct)
+                            .map_err(DeviceManagerError::CreateQcowDiskSync)?,
+                    ) as Box<dyn DiskFile>
                 }
             };