fix(dmsquash-live-root): check kernel for built-in overlay drivers

FGrose · johannbg · commit d0cd7cd38711 · 2022-08-12T10:25:00.000Z
Do not assume that `overlay` is always a module.  Check first for
`overlay` in `/proc/filesystems`. This is needed in the --no-kernel
use case to avoid the error: modprobe:
  FATAL: Module overlay not found in directory /lib/modules/&lt;kver&gt;

Signed-off-by: Federico Vaga &lt;federico.vaga@cern.ch&gt;
diff --git a/modules.d/90dmsquash-live/dmsquash-live-root.sh b/modules.d/90dmsquash-live/dmsquash-live-root.sh
@@ -177,7 +177,7 @@ do_live_overlay() {
         fi
     fi
     if [ -n "$overlayfs" ]; then
-        if ! modprobe overlay; then
+        if ! { strstr "$(< /proc/filesystems)" overlay || modprobe overlay; }; then
             if [ "$overlayfs" = required ]; then
                 die "OverlayFS is required but not available."
                 exit 1
