stress: Add --vfs <io-method> command line option

...unlocks io_uring stress runs.

stress/main.rs

@@ -476,9 +476,15 @@ async fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
         tempfile.path().to_string_lossy().to_string()
     };
 
+    let vfs_option = opts.vfs.clone();
+
     for thread in 0..opts.nr_threads {
         let db_file = db_file.clone();
-        let db = Arc::new(Mutex::new(Builder::new_local(&db_file).build().await?));
+        let mut builder = Builder::new_local(&db_file);
+        if let Some(ref vfs) = vfs_option {
+            builder = builder.with_io(vfs.clone());
+        }
+        let db = Arc::new(Mutex::new(builder.build().await?));
         let plan = plan.clone();
         let conn = db.lock().await.connect()?;
 
@@ -507,6 +513,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
 
         let nr_iterations = opts.nr_iterations;
         let db = db.clone();
+        let vfs_for_task = vfs_option.clone();
 
         let handle = tokio::spawn(async move {
             let mut conn = db.lock().await.connect()?;
@@ -518,7 +525,11 @@ async fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
                     }
                     // Reopen the database
                     let mut db_guard = db.lock().await;
-                    *db_guard = Builder::new_local(&db_file).build().await?;
+                    let mut builder = Builder::new_local(&db_file);
+                    if let Some(ref vfs) = vfs_for_task {
+                        builder = builder.with_io(vfs.clone());
+                    }
+                    *db_guard = builder.build().await?;
                     conn = db_guard.connect()?;
                 } else if gen_bool(0.01) {
                     // Reconnect to the database

stress/opts.rs

@@ -55,4 +55,11 @@ pub struct Opts {
     /// Database file
     #[clap(short = 'd', long, help = "database file")]
     pub db_file: Option<String>,
+
+    /// Select VFS
+    #[clap(
+        long,
+        help = "Select VFS. options are io_uring (if feature enabled), memory, and syscall"
+    )]
+    pub vfs: Option<String>,
 }