Vendor in container storage

This should add quota support to cri-o

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

vendor/github.com/containers/storage/drivers/overlay/check.go

@@ -0,0 +1,79 @@
+// +build linux
+
+package overlay
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path"
+	"path/filepath"
+
+	"github.com/containers/storage/pkg/system"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+	"golang.org/x/sys/unix"
+)
+
+// hasOpaqueCopyUpBug checks whether the filesystem has a bug
+// which copies up the opaque flag when copying up an opaque
+// directory. When this bug exists naive diff should be used.
+func hasOpaqueCopyUpBug(d string) error {
+	td, err := ioutil.TempDir(d, "opaque-bug-check")
+	if err != nil {
+		return err
+	}
+	defer func() {
+		if err := os.RemoveAll(td); err != nil {
+			logrus.Warnf("Failed to remove check directory %v: %v", td, err)
+		}
+	}()
+
+	// Make directories l1/d, l2/d, l3, work, merged
+	if err := os.MkdirAll(filepath.Join(td, "l1", "d"), 0755); err != nil {
+		return err
+	}
+	if err := os.MkdirAll(filepath.Join(td, "l2", "d"), 0755); err != nil {
+		return err
+	}
+	if err := os.Mkdir(filepath.Join(td, "l3"), 0755); err != nil {
+		return err
+	}
+	if err := os.Mkdir(filepath.Join(td, "work"), 0755); err != nil {
+		return err
+	}
+	if err := os.Mkdir(filepath.Join(td, "merged"), 0755); err != nil {
+		return err
+	}
+
+	// Mark l2/d as opaque
+	if err := system.Lsetxattr(filepath.Join(td, "l2", "d"), "trusted.overlay.opaque", []byte("y"), 0); err != nil {
+		return errors.Wrap(err, "failed to set opaque flag on middle layer")
+	}
+
+	opts := fmt.Sprintf("lowerdir=%s:%s,upperdir=%s,workdir=%s", path.Join(td, "l2"), path.Join(td, "l1"), path.Join(td, "l3"), path.Join(td, "work"))
+	if err := unix.Mount("overlay", filepath.Join(td, "merged"), "overlay", 0, opts); err != nil {
+		return errors.Wrap(err, "failed to mount overlay")
+	}
+	defer func() {
+		if err := unix.Unmount(filepath.Join(td, "merged"), 0); err != nil {
+			logrus.Warnf("Failed to unmount check directory %v: %v", filepath.Join(td, "merged"), err)
+		}
+	}()
+
+	// Touch file in d to force copy up of opaque directory "d" from "l2" to "l3"
+	if err := ioutil.WriteFile(filepath.Join(td, "merged", "d", "f"), []byte{}, 0644); err != nil {
+		return errors.Wrap(err, "failed to write to merged directory")
+	}
+
+	// Check l3/d does not have opaque flag
+	xattrOpaque, err := system.Lgetxattr(filepath.Join(td, "l3", "d"), "trusted.overlay.opaque")
+	if err != nil {
+		return errors.Wrap(err, "failed to read opaque flag on upper layer")
+	}
+	if string(xattrOpaque) == "y" {
+		return errors.New("opaque flag erroneously copied up, consider update to kernel 4.8 or later to fix")
+	}
+
+	return nil
+}