fix(s3stream/wal): no need to create the file when checking dio (#934)

Signed-off-by: Ning Yu <[email protected]>

s3stream/src/main/java/com/automq/stream/s3/wal/benchmark/RecoveryBench.java

@@ -101,8 +101,8 @@ static class Config {
         Config(Namespace ns) {
             this.path = ns.getString("path");
             this.capacity = ns.getLong("capacity");
-            this.numRecords = ns.getInt("numRecords");
-            this.recordSizeBytes = ns.getInt("recordSizeBytes");
+            this.numRecords = ns.getInt("records");
+            this.recordSizeBytes = ns.getInt("recordSize");
         }
 
         static ArgumentParser parser() {
@@ -123,6 +123,7 @@ static ArgumentParser parser() {
                 .setDefault(1 << 20)
                 .help("number of records to write");
             parser.addArgument("--record-size")
+                .dest("recordSize")
                 .type(Integer.class)
                 .setDefault(1 << 10)
                 .help("size of each record in bytes");

s3stream/src/main/java/com/automq/stream/s3/wal/util/WALBlockDeviceChannel.java

@@ -98,28 +98,28 @@ public static String checkAvailable(String path) {
             return "java.nio.DirectByteBuffer.<init>(long, int) not available." +
                 " Add --add-opens=java.base/java.nio=ALL-UNNAMED and -Dio.netty.tryReflectionSetAccessible=true to JVM options may fix this.";
         }
-        if (!path.startsWith(DEVICE_PREFIX) && !tryOpenFileWithDirectIO(String.format(CHECK_DIRECT_IO_AVAILABLE_FORMAT, path))) {
-            return "O_DIRECT not supported by the file system, path: " + path;
+        if (!path.startsWith(DEVICE_PREFIX)) {
+            String reason = tryOpenFileWithDirectIO(String.format(CHECK_DIRECT_IO_AVAILABLE_FORMAT, path));
+            if (null != reason) {
+                return "O_DIRECT not supported by the file system, path: " + path + ", reason: " + reason;
+            }
         }
         return null;
     }
 
     /**
-     * Try to create a file with O_DIRECT flag to check whether the file system supports O_DIRECT.
-     * The file will be deleted after created.
+     * Try to open a file with O_DIRECT flag to check whether the file system supports O_DIRECT.
+     * NOTE: The file is not actually created.
      *
-     * @return true if the file is created successfully, otherwise false
+     * @return null if the file is opened successfully, otherwise the reason why it's not available
      */
-    private static boolean tryOpenFileWithDirectIO(String path) {
-        File file = new File(path);
+    private static String tryOpenFileWithDirectIO(String path) {
         try {
-            DirectRandomAccessFile randomAccessFile = new DirectRandomAccessFile(file, "rw");
+            DirectRandomAccessFile randomAccessFile = new DirectRandomAccessFile(new File(path), "rw");
             randomAccessFile.close();
-            return true;
+            return null;
         } catch (IOException e) {
-            return false;
-        } finally {
-            file.delete();
+            return e.getMessage();
         }
     }