Add slack channel link to corrupted disk err msg (#4270)

cmd/fs-v1_test.go

@@ -21,6 +21,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"strings"
 	"testing"
 
 	"github.com/minio/minio/pkg/lock"
@@ -173,8 +174,7 @@ func TestFSMigrateObjectWithErr(t *testing.T) {
 	}
 
 	if err = initFormatFS(disk, uuid); err != nil {
-		if errorCause(err).Error() !=
+		if !strings.Contains(errorCause(err).Error(), "Unable to validate 'format.json', corrupted backend format") {
-			"Unable to validate 'format.json', corrupted backend format" {
 			t.Fatal("Should not fail with unexpected", err)
 		}
 	}

cmd/storage-errors.go

@@ -22,7 +22,7 @@ import "errors"
 var errUnexpected = errors.New("Unexpected error, please report this issue at https://github.com/minio/minio/issues")
 
 // errCorruptedFormat - corrupted backend format.
-var errCorruptedFormat = errors.New("corrupted backend format")
+var errCorruptedFormat = errors.New("corrupted backend format, please join https://slack.minio.io for assistance")
 
 // errUnformattedDisk - unformatted disk found.
 var errUnformattedDisk = errors.New("unformatted disk found")