http2 throws custom error Content-Length shorter handle it

We should internally handle when http2 input stream has smaller
content than its content-length header

Upstream issue reported golang/go#30648

This a change which we need to handle internally until Go fixes it
correctly, till now our code doesn't expect a custom error to be returned.

Author: harshavardhana

cmd/fs-v1-helpers.go

@@ -344,20 +344,23 @@ func fsCreateFile(ctx context.Context, filePath string, reader io.Reader, buf []
 	var bytesWritten int64
 	if buf != nil {
 		bytesWritten, err = io.CopyBuffer(writer, reader, buf)
-		if err != nil {
-			if err != io.ErrUnexpectedEOF {
-				logger.LogIf(ctx, err)
-			}
-			return 0, err
-		}
 	} else {
 		bytesWritten, err = io.Copy(writer, reader)
-		if err != nil {
+	}
+	if fallocSize > 0 {
+		if bytesWritten < fallocSize {
+			err = io.ErrUnexpectedEOF
+		}
+		if bytesWritten > fallocSize {
+			err = io.ErrUnexpectedEOF
+		}
+	}
+	if err != nil {
+		if err != io.ErrUnexpectedEOF {
 			logger.LogIf(ctx, err)
-			return 0, err
 		}
+		return 0, err
 	}
-
 	return bytesWritten, nil
 }
 

cmd/posix.go

@@ -1091,16 +1091,13 @@ func (s *posix) CreateFile(volume, path string, fileSize int64, r io.Reader) (er
 	defer s.pool.Put(bufp)
 
 	n, err := io.CopyBuffer(w, r, *bufp)
-	if err != nil {
-		return err
-	}
 	if n < fileSize {
 		return errLessData
 	}
 	if n > fileSize {
 		return errMoreData
 	}
-	return nil
+	return err
 }
 
 func (s *posix) WriteAll(volume, path string, buf []byte) (err error) {