Patch to fix the problem on singularity-3.1 described in https://stackoverflow.com/questions/63061424/squashfs-error-when-running-singularity-after-ubuntu-upgrade

mount_error_fix.patch

--- a/internal/pkg/util/fs/mount/mount.go
+++ b/internal/pkg/util/fs/mount/mount.go
@@ -585,7 +585,10 @@
 	if sizelimit == 0 {
 		return fmt.Errorf("invalid image size, zero length")
 	}
-	options = fmt.Sprintf("loop,offset=%d,sizelimit=%d,errors=remount-ro", offset, sizelimit)
+	options = fmt.Sprintf("loop,offset=%d,sizelimit=%d", offset, sizelimit)
+	if fstype == "ext3" {
+		options += ",errors=remount-ro"
+	}
 	return p.add(tag, source, dest, fstype, flags, options)
 }