containerd · TBBle · Dec 12, 2020 · Aug 10, 2022 · Jul 23, 2020 · Jul 23, 2020
diff --git a/diff/windows/windows.go b/diff/windows/windows.go
@@ -311,10 +311,13 @@ func mountsToLayerAndParents(mounts []mount.Mount) (string, []string, error) {
 		return "", nil, fmt.Errorf("number of mounts should always be 1 for Windows layers: %w", errdefs.ErrInvalidArgument)
 	}
 	mnt := mounts[0]
-	if mnt.Type != "windows-layer" {
+
+	if mnt.Type != "windows-layer" && mnt.Type != "bind" {
 		// This is a special case error. When this is received the diff service
 		// will attempt the next differ in the chain which for Windows is the
 		// lcow differ that we want.
+		// TODO: Is there any situation where we actually wanted a "bind" mount to
+		// fall through to the lcow differ?
 		return "", nil, fmt.Errorf("windowsDiff does not support layer type %s: %w", mnt.Type, errdefs.ErrNotImplemented)
 	}
 
@@ -323,6 +326,30 @@ func mountsToLayerAndParents(mounts []mount.Mount) (string, []string, error) {
 		return "", nil, err
 	}
 
+	isView := false
+	for _, o := range mnt.Options {
+		if o == "ro" {
+			isView = true
+			break
+		}
+	}
+
+	if isView {
+		if mnt.Type == "bind" && len(parentLayerPaths) != 0 {
+			return "", nil, fmt.Errorf("unexpected bind-mount View with parents: %w", errdefs.ErrInvalidArgument)
+		} else if mnt.Type == "bind" {
+			// rootfs.CreateDiff creates a new, empty View to diff against,
+			// when diffing something with no parent.
+			// This makes perfect sense for a walking Diff, but for WCOW,
+			// we have to recognise this as "diff against nothing"
+			return "", nil, nil
+		} else if len(parentLayerPaths) == 0 {
+			return "", nil, fmt.Errorf("unexpected windows-layer View with no parent: %w", errdefs.ErrInvalidArgument)
+		}
+		// Ignore the dummy sandbox.
+		return parentLayerPaths[0], parentLayerPaths[1:], nil
+	}
+
 	return mnt.Source, parentLayerPaths, nil
 }
 
@@ -337,8 +364,16 @@ func mountPairToLayerStack(lower, upper []mount.Mount) ([]string, error) {
 		return nil, fmt.Errorf("Upper mount invalid: %w", err)
 	}
 
+	lowerLayer, lowerParentLayerPaths, err := mountsToLayerAndParents(lower)
+	if errdefs.IsNotImplemented(err) {
+		// Upper was a windows-layer or bind, lower is not. We can't handle that.
+		return nil, fmt.Errorf("windowsDiff cannot diff a windows-layer against a non-windows-layer: %w", errdefs.ErrInvalidArgument)
+	} else if err != nil {
+		return nil, fmt.Errorf("Lower mount invalid: %w", err)
+	}
+
 	// Trivial case, diff-against-nothing
-	if len(lower) == 0 {
+	if lowerLayer == "" {
 		if len(upperParentLayerPaths) != 0 {
 			return nil, fmt.Errorf("windowsDiff cannot diff a layer with parents against a null layer: %w", errdefs.ErrInvalidArgument)
 		}
@@ -349,14 +384,6 @@ func mountPairToLayerStack(lower, upper []mount.Mount) ([]string, error) {
 		return nil, fmt.Errorf("windowsDiff cannot diff a layer with no parents against another layer: %w", errdefs.ErrInvalidArgument)
 	}
 
-	lowerLayer, lowerParentLayerPaths, err := mountsToLayerAndParents(lower)
-	if errdefs.IsNotImplemented(err) {
-		// Upper was a windows-layer, lower is not. We can't handle that.
-		return nil, fmt.Errorf("windowsDiff cannot diff a windows-layer against a non-windows-layer: %w", errdefs.ErrInvalidArgument)
-	} else if err != nil {
-		return nil, fmt.Errorf("Lower mount invalid: %w", err)
-	}
-
 	if upperParentLayerPaths[0] != lowerLayer {
 		return nil, fmt.Errorf("windowsDiff cannot diff a layer against a layer other than its own parent: %w", errdefs.ErrInvalidArgument)
 	}

diff --git a/go.mod b/go.mod
@@ -11,7 +11,7 @@ require (
 	github.com/containerd/btrfs v1.0.0
 	github.com/containerd/cgroups v1.0.4
 	github.com/containerd/console v1.0.3
-	github.com/containerd/continuity v0.3.0
+	github.com/containerd/continuity v0.3.1-0.20220810172617-b4ca35286886
 	github.com/containerd/fifo v1.0.0
 	github.com/containerd/go-cni v1.1.6
 	github.com/containerd/go-runc v1.0.0
@@ -30,7 +30,7 @@ require (
 	github.com/emicklei/go-restful/v3 v3.8.0
 	github.com/fsnotify/fsnotify v1.5.1
 	github.com/google/go-cmp v0.5.8
-	github.com/google/uuid v1.2.0
+	github.com/google/uuid v1.3.0
 	github.com/grpc-ecosystem/go-grpc-middleware v1.3.0
 	github.com/grpc-ecosystem/go-grpc-prometheus v1.2.0
 	github.com/hashicorp/go-multierror v1.1.1
@@ -87,6 +87,7 @@ require (
 	github.com/cpuguy83/go-md2man/v2 v2.0.1 // indirect
 	github.com/cyphar/filepath-securejoin v0.2.3 // indirect
 	github.com/emicklei/go-restful v2.9.5+incompatible // indirect
+	github.com/gabriel-samfira/go-hivex v0.0.0-20190725123041-b40bc95a7ced // indirect
 	github.com/go-logr/logr v1.2.3 // indirect
 	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/godbus/dbus/v5 v5.0.6 // indirect
@@ -122,11 +123,14 @@ require (
 	go.opentelemetry.io/otel/exporters/otlp/internal/retry v1.7.0 // indirect
 	go.opentelemetry.io/proto/otlp v0.16.0 // indirect
 	golang.org/x/crypto v0.0.0-20220315160706-3147a52a75dd // indirect
+	golang.org/x/mod v0.6.0-dev.0.20220106191415-9b9b3d81d5e3 // indirect
 	golang.org/x/net v0.0.0-20220425223048-2871e0cb64e4 // indirect
 	golang.org/x/oauth2 v0.0.0-20211104180415-d3ed0bb246c8 // indirect
 	golang.org/x/term v0.0.0-20210927222741-03fcf44c2211 // indirect
 	golang.org/x/text v0.3.7 // indirect
 	golang.org/x/time v0.0.0-20220210224613-90d013bbcef8 // indirect
+	golang.org/x/tools v0.1.10-0.20220218145154-897bd77cd717 // indirect
+	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
 	google.golang.org/appengine v1.6.7 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect
 	gopkg.in/square/go-jose.v2 v2.5.1 // indirect
@@ -136,3 +140,5 @@ require (
 	sigs.k8s.io/structured-merge-diff/v4 v4.2.1 // indirect
 	sigs.k8s.io/yaml v1.3.0 // indirect
 )
+
+replace github.com/Microsoft/hcsshim => github.com/TBBle/hcsshim v0.10.0-rc.0.0.20220811170900-035362c035c9