backend/s3: better error msg
@@ -54,7 +54,7 @@ func (sb *s3Backend) Save(version string, snapRev int64, rc io.Reader) (int64, e
n, err := io.Copy(tmpfile, rc)
if err != nil {
- return -1, fmt.Errorf("failed to save snapshot: %v", err)
+ return -1, fmt.Errorf("failed to save snapshot to tmpfile: %v", err)
}
_, err = tmpfile.Seek(0, os.SEEK_SET)
if err != nil {
