From 33121d3d4526d7e5315cc1dd20e194bdf699486f Mon Sep 17 00:00:00 2001
From: Nicolas De Loof <nicolas.deloof@gmail.com>
Date: Wed, 22 Jun 2022 09:05:21 +0200
Subject: [PATCH] introduce Containerd-snapshotter feature flag

Signed-off-by: Nicolas De Loof <nicolas.deloof@gmail.com>
---
 daemon/daemon.go    | 10 ++++++++++
 daemon/oci_linux.go | 10 ++++++----
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/daemon/daemon.go b/daemon/daemon.go
index bb09038b63..f9c91d89ce 100644
--- a/daemon/daemon.go
+++ b/daemon/daemon.go
@@ -146,6 +146,16 @@ func (daemon *Daemon) Features() *map[string]bool {
 	return &daemon.configStore.Features
 }
 
+// usesSnapshotter returns true if feature flag to use containerd snapshotter is enabled
+func (daemon *Daemon) usesSnapshotter() bool {
+	if daemon.configStore.Features != nil {
+		if b, ok := daemon.configStore.Features["containerd-snapshotter"]; ok {
+			return b
+		}
+	}
+	return false
+}
+
 // RegistryHosts returns registry configuration in containerd resolvers format
 func (daemon *Daemon) RegistryHosts() docker.RegistryHosts {
 	var (
diff --git a/daemon/oci_linux.go b/daemon/oci_linux.go
index 8deeed2b86..07caa78bc3 100644
--- a/daemon/oci_linux.go
+++ b/daemon/oci_linux.go
@@ -720,16 +720,18 @@ func sysctlExists(s string) bool {
 // WithCommonOptions sets common docker options
 func WithCommonOptions(daemon *Daemon, c *container.Container) coci.SpecOpts {
 	return func(ctx context.Context, _ coci.Client, _ *containers.Container, s *coci.Spec) error {
-		if c.BaseFS == nil {
+		if c.BaseFS == nil && !daemon.usesSnapshotter() {
 			return errors.New("populateCommonSpec: BaseFS of container " + c.ID + " is unexpectedly nil")
 		}
 		linkedEnv, err := daemon.setupLinkedContainers(c)
 		if err != nil {
 			return err
 		}
-		s.Root = &specs.Root{
-			Path:     c.BaseFS.Path(),
-			Readonly: c.HostConfig.ReadonlyRootfs,
+		if !daemon.usesSnapshotter() {
+			s.Root = &specs.Root{
+				Path:     c.BaseFS.Path(),
+				Readonly: c.HostConfig.ReadonlyRootfs,
+			}
 		}
 		if err := c.SetupWorkingDirectory(daemon.idMapping.RootPair()); err != nil {
 			return err