Minor changes

- update zdfs package version to v0.1.4
- update snapshotter config doc
- add isPrepareRootfs() method to check if current prepared layer
  is a rootfs layer or image layer.

Signed-off-by: Yifan Yuan <tuji.yyf@alibaba-inc.com>

Author: BigVan

docs/QUICKSTART.md

@@ -54,6 +54,7 @@ After download, install the rpm/deb package.
 #### Config
 
 The config file is `/etc/overlaybd-snapshotter/config.json`. Please create the file if not exists.
+**We suggest the root path of snapshotter is a subpath of containerd's root**
 
 ```json
 {
@@ -82,7 +83,7 @@ The config file is `/etc/overlaybd-snapshotter/config.json`. Please create the f
 ```
 | Field | Description |
 | ----- | ----------- |
-| `root` | the root directory to store snapshots |
+| `root` | the root directory to store snapshots. **Suggestion: This path should be a subpath of containerd's root** |
 | `address` | the socket address used to connect withcontainerd. |
 | `verbose` | log level, `info` or `debug` |
 | `rwMode` | rootfs mode about wether to use native writable layer. See [Native Support for Writable](./WRITABLE.md) for detail. |

go.mod

@@ -7,7 +7,7 @@ require (
 	github.com/containerd/continuity v0.4.3
 	github.com/containerd/go-cni v1.1.9
 	github.com/containerd/log v0.1.0
-	github.com/data-accelerator/zdfs v0.1.3
+	github.com/data-accelerator/zdfs v0.1.4
 	github.com/go-sql-driver/mysql v1.6.0
 	github.com/jessevdk/go-flags v1.5.0
 	github.com/moby/locker v1.0.1

go.sum

@@ -107,8 +107,8 @@ github.com/cpuguy83/go-md2man/v2 v2.0.0/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsr
 github.com/cpuguy83/go-md2man/v2 v2.0.2 h1:p1EgwI/C7NhT0JmVkwCD2ZBK8j4aeHQX2pMHHBfMQ6w=
 github.com/cpuguy83/go-md2man/v2 v2.0.2/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
 github.com/cyphar/filepath-securejoin v0.2.3/go.mod h1:aPGpWjXOXUn2NCNjFvBE6aRxGGx79pTxQpKOJNYHHl4=
-github.com/data-accelerator/zdfs v0.1.3 h1:fhe2PiV+JvauZ2rBFguEM8/DcFkxtJI+6973E24zTWM=
-github.com/data-accelerator/zdfs v0.1.3/go.mod h1:MnDNsg9RiB+Ey0DzOOQ5sdMSyS8fGKGbcOYI1VULSPI=
+github.com/data-accelerator/zdfs v0.1.4 h1:S7M1lpnVPDANXXXD1ZI6p3ZUempNYVLxUkXbgEUVUkM=
+github.com/data-accelerator/zdfs v0.1.4/go.mod h1:MnDNsg9RiB+Ey0DzOOQ5sdMSyS8fGKGbcOYI1VULSPI=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=

pkg/label/label.go

@@ -95,6 +95,8 @@ const (
 
 	// LayerToTurboOCI is used to convert local layer to turboOCI with tar index
 	LayerToTurboOCI = "containerd.io/snapshot/overlaybd/convert2turbo-oci"
+
+	SnapshotType = "containerd.io/snapshot/type"
 )
 
 // used in filterAnnotationsForSave (https://github.com/moby/buildkit/blob/v0.11/cache/refs.go#L882)

pkg/snapshot/overlay.go

@@ -364,6 +364,16 @@ func (o *snapshotter) checkTurboOCI(labels map[string]string) (bool, string, str
 	return false, "", ""
 }
 
+func (o *snapshotter) isPrepareRootfs(info snapshots.Info) bool {
+	if _, ok := info.Labels[label.TargetSnapshotRef]; ok {
+		return false
+	}
+	if info.Labels[label.SnapshotType] == "image" {
+		return false
+	}
+	return true
+}
+
 func (o *snapshotter) createMountPoint(ctx context.Context, kind snapshots.Kind, key string, parent string, opts ...snapshots.Opt) (_ []mount.Mount, retErr error) {
 
 	ctx, t, err := o.ms.TransactionContext(ctx, true)
@@ -384,6 +394,7 @@ func (o *snapshotter) createMountPoint(ctx context.Context, kind snapshots.Kind,
 	if err != nil {
 		return nil, err
 	}
+	log.G(ctx).Infof("sn: %s, labels:[%+v]", id, info.Labels)
 	defer func() {
 		// the transaction rollback makes created snapshot invalid, just clean it.
 		if retErr != nil && rollback {
@@ -495,8 +506,8 @@ func (o *snapshotter) createMountPoint(ctx context.Context, kind snapshots.Kind,
 	writeType := o.getWritableType(ctx, parentID, info)
 
 	// If Preparing for rootfs, find metadata from its parent (top layer), launch and mount backstore device.
-	if _, ok := info.Labels[label.TargetSnapshotRef]; !ok {
-		log.G(ctx).Infof("Preparing rootfs. writeType: %s", writeType)
+	if o.isPrepareRootfs(info) {
+		log.G(ctx).Infof("Preparing rootfs(%s). writeType: %s", s.ID, writeType)
 		if writeType != RoDir {
 			stype = storageTypeLocalBlock
 			if err := o.constructOverlayBDSpec(ctx, key, true); err != nil {
@@ -515,8 +526,8 @@ func (o *snapshotter) createMountPoint(ctx context.Context, kind snapshots.Kind,
 				parentIsAccelLayer := parentInfo.Labels[label.AccelerationLayer] == "yes"
 				needRecordTrace := info.Labels[label.RecordTrace] == "yes"
 				recordTracePath := info.Labels[label.RecordTracePath]
-				log.G(ctx).Infof("Prepare rootfs (parentIsAccelLayer: %t, needRecordTrace: %t, recordTracePath: %s)",
-					parentIsAccelLayer, needRecordTrace, recordTracePath)
+				log.G(ctx).Infof("Prepare rootfs (sn: %s, parentIsAccelLayer: %t, needRecordTrace: %t, recordTracePath: %s)",
+					id, parentIsAccelLayer, needRecordTrace, recordTracePath)
 
 				if parentIsAccelLayer {
 					log.G(ctx).Infof("get accel-layer in parent (id: %s)", id)