Add fs prefix (directory)

This ensures the fs root is clean and does not mess with
the metadata. Also in the future this will allow for multiple
filesystems to be created in one bucket.

pkg/s3/s3-client.go

@@ -13,6 +13,7 @@ import (
 
 const (
 	metadataName = ".metadata.json"
+	fsPrefix     = "csi-fs"
 )
 
 type s3Client struct {
@@ -22,6 +23,7 @@ type s3Client struct {
 
 type bucket struct {
 	Name          string
+	FSPath        string
 	CapacityBytes int64
 }
 
@@ -54,6 +56,14 @@ func (client *s3Client) createBucket(bucketName string) error {
 	return client.minio.MakeBucket(bucketName, client.cfg.Region)
 }
 
+func (client *s3Client) createPrefix(bucketName string, prefix string) error {
+	_, err := client.minio.PutObject(bucketName, prefix+"/", bytes.NewReader([]byte("")), 0, minio.PutObjectOptions{})
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
 func (client *s3Client) removeBucket(bucketName string) error {
 	if err := client.emptyBucket(bucketName); err != nil {
 		return err