block: merge qcow, vhdx and block_util into block crate

This commit merges crates `qcow`, `vhdx` and `block_util` into the
crate `block`, which can allow `qcow` to use functions from `block_util`
without introducing a circular crate dependency.

This commit is based on crosvm implementation:
https://chromium.googlesource.com/crosvm/crosvm/+/f2eecc4152eca8d395566cffa2c102ec090a152d

Signed-off-by: Yu Li <liyu.yukiteru@bytedance.com>

virtio-devices/src/block.rs

@@ -19,7 +19,7 @@ use crate::thread_helper::spawn_virtio_thread;
 use crate::GuestMemoryMmap;
 use crate::VirtioInterrupt;
 use anyhow::anyhow;
-use block_util::{
+use block::{
     async_io::AsyncIo, async_io::AsyncIoError, async_io::DiskFile, build_disk_image_id, Request,
     RequestType, VirtioBlockConfig,
 };
@@ -63,11 +63,11 @@ const LATENCY_SCALE: u64 = 10000;
 #[derive(Error, Debug)]
 pub enum Error {
     #[error("Failed to parse the request: {0}")]
-    RequestParsing(block_util::Error),
+    RequestParsing(block::Error),
     #[error("Failed to execute the request: {0}")]
-    RequestExecuting(block_util::ExecuteError),
+    RequestExecuting(block::ExecuteError),
     #[error("Failed to complete the request: {0}")]
-    RequestCompleting(block_util::Error),
+    RequestCompleting(block::Error),
     #[error("Missing the expected entry in the list of requests")]
     MissingEntryRequestList,
     #[error("The asynchronous request returned with failure")]

virtio-devices/src/vhost_user/blk.rs

@@ -9,7 +9,7 @@ use crate::thread_helper::spawn_virtio_thread;
 use crate::vhost_user::VhostUserCommon;
 use crate::{GuestMemoryMmap, GuestRegionMmap};
 use crate::{VirtioInterrupt, VIRTIO_F_IOMMU_PLATFORM};
-use block_util::VirtioBlockConfig;
+use block::VirtioBlockConfig;
 use seccompiler::SeccompAction;
 use std::mem;
 use std::result;