From 92243ff72aa315b4b56e947d4e70b29e92bf8637 Mon Sep 17 00:00:00 2001
From: Michael Wan <zirenwan@gmail.com>
Date: Wed, 29 Aug 2018 07:32:01 -0400
Subject: [PATCH] bugfix: updatedAt timestamp file may be empty

Signed-off-by: Michael Wan <zirenwan@gmail.com>
---
 content/local/store.go       |  4 +++-
 content/local/store_test.go  | 22 ++++++++++++++++++++++
 snapshots/btrfs/btrfs.go     |  3 ++-
 snapshots/native/native.go   |  5 +++--
 snapshots/overlay/overlay.go |  4 ++--
 5 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/content/local/store.go b/content/local/store.go
index 6df3df618..7fa9bb736 100644
--- a/content/local/store.go
+++ b/content/local/store.go
@@ -33,6 +33,8 @@ import (
 	"github.com/containerd/containerd/errdefs"
 	"github.com/containerd/containerd/filters"
 	"github.com/containerd/containerd/log"
+
+	"github.com/containerd/continuity"
 	digest "github.com/opencontainers/go-digest"
 	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 	"github.com/pkg/errors"
@@ -651,5 +653,5 @@ func writeTimestampFile(p string, t time.Time) error {
 		return err
 	}
 
-	return ioutil.WriteFile(p, b, 0666)
+	return continuity.AtomicWriteFile(p, b, 0666)
 }
diff --git a/content/local/store_test.go b/content/local/store_test.go
index e51638ab0..54e90c7cf 100644
--- a/content/local/store_test.go
+++ b/content/local/store_test.go
@@ -36,6 +36,7 @@ import (
 	"github.com/containerd/containerd/content"
 	"github.com/containerd/containerd/content/testsuite"
 	"github.com/containerd/containerd/pkg/testutil"
+
 	"github.com/opencontainers/go-digest"
 	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 	"gotest.tools/assert"
@@ -392,3 +393,24 @@ func setupIncompleteWrite(ctx context.Context, t *testing.T, cs content.Store, r
 
 	assert.NilError(t, writer.Close())
 }
+
+func TestWriteReadEmptyFileTimestamp(t *testing.T) {
+	root, err := ioutil.TempDir("", "test-write-read-file-timestamp")
+	if err != nil {
+		t.Errorf("failed to create a tmp dir: %v", err)
+	}
+	defer os.RemoveAll(root)
+
+	emptyFile := filepath.Join(root, "updatedat")
+	if err := writeTimestampFile(emptyFile, time.Time{}); err != nil {
+		t.Errorf("failed to write Zero Time to file: %v", err)
+	}
+
+	timestamp, err := readFileTimestamp(emptyFile)
+	if err != nil {
+		t.Errorf("read empty timestamp file should success, but got error: %v", err)
+	}
+	if !timestamp.IsZero() {
+		t.Errorf("read empty timestamp file should return time.Time{}, but got: %v", timestamp)
+	}
+}
diff --git a/snapshots/btrfs/btrfs.go b/snapshots/btrfs/btrfs.go
index e2cedbef3..a89b55129 100644
--- a/snapshots/btrfs/btrfs.go
+++ b/snapshots/btrfs/btrfs.go
@@ -33,6 +33,7 @@ import (
 	"github.com/containerd/containerd/snapshots"
 	"github.com/containerd/containerd/snapshots/storage"
 	"github.com/containerd/continuity/fs"
+
 	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
@@ -171,7 +172,7 @@ func (b *snapshotter) usage(ctx context.Context, key string) (snapshots.Usage, e
 		if parentID != "" {
 			du, err = fs.DiffUsage(ctx, filepath.Join(b.root, "snapshots", parentID), p)
 		} else {
-			du, err = fs.DiskUsage(p)
+			du, err = fs.DiskUsage(ctx, p)
 		}
 		if err != nil {
 			// TODO(stevvooe): Consider not reporting an error in this case.
diff --git a/snapshots/native/native.go b/snapshots/native/native.go
index 821f13e6a..0b9c3befc 100644
--- a/snapshots/native/native.go
+++ b/snapshots/native/native.go
@@ -28,6 +28,7 @@ import (
 	"github.com/containerd/containerd/plugin"
 	"github.com/containerd/containerd/snapshots"
 	"github.com/containerd/containerd/snapshots/storage"
+
 	"github.com/containerd/continuity/fs"
 	"github.com/pkg/errors"
 )
@@ -120,7 +121,7 @@ func (o *snapshotter) Usage(ctx context.Context, key string) (snapshots.Usage, e
 	}
 
 	if info.Kind == snapshots.KindActive {
-		du, err := fs.DiskUsage(o.getSnapshotDir(id))
+		du, err := fs.DiskUsage(ctx, o.getSnapshotDir(id))
 		if err != nil {
 			return snapshots.Usage{}, err
 		}
@@ -166,7 +167,7 @@ func (o *snapshotter) Commit(ctx context.Context, name, key string, opts ...snap
 		return err
 	}
 
-	usage, err := fs.DiskUsage(o.getSnapshotDir(id))
+	usage, err := fs.DiskUsage(ctx, o.getSnapshotDir(id))
 	if err != nil {
 		return err
 	}
diff --git a/snapshots/overlay/overlay.go b/snapshots/overlay/overlay.go
index 0650e7878..2c296adbe 100644
--- a/snapshots/overlay/overlay.go
+++ b/snapshots/overlay/overlay.go
@@ -168,7 +168,7 @@ func (o *snapshotter) Usage(ctx context.Context, key string) (snapshots.Usage, e
 	upperPath := o.upperPath(id)
 
 	if info.Kind == snapshots.KindActive {
-		du, err := fs.DiskUsage(upperPath)
+		du, err := fs.DiskUsage(ctx, upperPath)
 		if err != nil {
 			// TODO(stevvooe): Consider not reporting an error in this case.
 			return snapshots.Usage{}, err
@@ -225,7 +225,7 @@ func (o *snapshotter) Commit(ctx context.Context, name, key string, opts ...snap
 		return err
 	}
 
-	usage, err := fs.DiskUsage(o.upperPath(id))
+	usage, err := fs.DiskUsage(ctx, o.upperPath(id))
 	if err != nil {
 		return err
 	}