From 0d0b2bd4fe0551464e1ab6adc39077e833be8746 Mon Sep 17 00:00:00 2001
From: Henry Wang <henwang@amazon.com>
Date: Tue, 8 Mar 2022 23:24:50 +0000
Subject: [PATCH] Mount devmapper xfs file system with "nouuid" option.

Two xfs file systems with same UUID can not be mounted on the same system.
However devmapper snapshots will have same UUID as original filesystem.

This patch fixes the bug by mounting a xfs file system with "nouuid" option.

Signed-off-by: Henry Wang <henwang@amazon.com>
---
 snapshots/devmapper/snapshotter.go      |   2 +
 snapshots/devmapper/snapshotter_test.go | 109 ++++++++++++++++++------
 2 files changed, 85 insertions(+), 26 deletions(-)

diff --git a/snapshots/devmapper/snapshotter.go b/snapshots/devmapper/snapshotter.go
index ca9867f49..1e2977966 100644
--- a/snapshots/devmapper/snapshotter.go
+++ b/snapshots/devmapper/snapshotter.go
@@ -504,6 +504,8 @@ func (s *Snapshotter) buildMounts(ctx context.Context, snap storage.Snapshot, fi
 	if fileSystemType == "" {
 		log.G(ctx).Error("File system type cannot be empty")
 		return nil
+	} else if fileSystemType == fsTypeXFS {
+		options = append(options, "nouuid")
 	}
 	if snap.Kind != snapshots.KindActive {
 		options = append(options, "ro")
diff --git a/snapshots/devmapper/snapshotter_test.go b/snapshots/devmapper/snapshotter_test.go
index 819a555d4..244c9845a 100644
--- a/snapshots/devmapper/snapshotter_test.go
+++ b/snapshots/devmapper/snapshotter_test.go
@@ -46,38 +46,13 @@ func TestSnapshotterSuite(t *testing.T) {
 	logrus.SetLevel(logrus.DebugLevel)
 
 	snapshotterFn := func(ctx context.Context, root string) (snapshots.Snapshotter, func() error, error) {
-		// Create loopback devices for each test case
-		_, loopDataDevice := createLoopbackDevice(t, root)
-		_, loopMetaDevice := createLoopbackDevice(t, root)
-
 		poolName := fmt.Sprintf("containerd-snapshotter-suite-pool-%d", time.Now().Nanosecond())
-		err := dmsetup.CreatePool(poolName, loopDataDevice, loopMetaDevice, 64*1024/dmsetup.SectorSize)
-		assert.NilError(t, err, "failed to create pool %q", poolName)
-
 		config := &Config{
 			RootPath:      root,
 			PoolName:      poolName,
 			BaseImageSize: "16Mb",
 		}
-
-		snap, err := NewSnapshotter(context.Background(), config)
-		if err != nil {
-			return nil, nil, err
-		}
-
-		// Remove device mapper pool and detach loop devices after test completes
-		removePool := func() error {
-			result := multierror.Append(
-				snap.pool.RemovePool(ctx),
-				mount.DetachLoopDevice(loopDataDevice, loopMetaDevice))
-
-			return result.ErrorOrNil()
-		}
-
-		// Pool cleanup should be called before closing metadata store (as we need to retrieve device names)
-		snap.cleanupFn = append([]closeFunc{removePool}, snap.cleanupFn...)
-
-		return snap, snap.Close, nil
+		return createSnapshotter(ctx, t, config)
 	}
 
 	testsuite.SnapshotterSuite(t, "devmapper", snapshotterFn)
@@ -165,3 +140,85 @@ func TestMkfsXfsNonDefault(t *testing.T) {
 	err := mkfs(ctx, "xfs", "noquota", "")
 	assert.ErrorContains(t, err, `mkfs.xfs couldn't initialize ""`)
 }
+
+func TestMultipleXfsMounts(t *testing.T) {
+	testutil.RequiresRoot(t)
+
+	logrus.SetLevel(logrus.DebugLevel)
+
+	ctx := context.Background()
+	ctx = namespaces.WithNamespace(ctx, "testsuite")
+	tempDir, err := os.MkdirTemp("", "snapshot-suite-usage")
+	assert.NilError(t, err)
+	defer os.RemoveAll(tempDir)
+
+	poolName := fmt.Sprintf("containerd-snapshotter-suite-pool-%d", time.Now().Nanosecond())
+	config := &Config{
+		RootPath:       tempDir,
+		PoolName:       poolName,
+		BaseImageSize:  "16Mb",
+		FileSystemType: "xfs",
+	}
+	snapshotter, closer, err := createSnapshotter(ctx, t, config)
+	assert.NilError(t, err)
+	defer closer()
+
+	var (
+		sizeBytes   int64 = 1048576 // 1MB
+		baseApplier       = fstest.Apply(fstest.CreateRandomFile("/a", 12345679, sizeBytes, 0777))
+	)
+
+	// Create base layer
+	mounts, err := snapshotter.Prepare(ctx, "prepare-1", "")
+	assert.NilError(t, err)
+
+	root1, _ := os.MkdirTemp(os.TempDir(), "containerd-mount")
+	defer func() {
+		mount.UnmountAll(root1, 0)
+		os.Remove(root1)
+	}()
+	err = mount.All(mounts, root1)
+	assert.NilError(t, err)
+	baseApplier.Apply(root1)
+	snapshotter.Commit(ctx, "layer-1", "prepare-1")
+
+	// Create one child layer
+	mounts, err = snapshotter.Prepare(ctx, "prepare-2", "layer-1")
+	assert.NilError(t, err)
+
+	root2, _ := os.MkdirTemp(os.TempDir(), "containerd-mount")
+	defer func() {
+		mount.UnmountAll(root2, 0)
+		os.Remove(root2)
+	}()
+	err = mount.All(mounts, root2)
+	assert.NilError(t, err)
+}
+
+func createSnapshotter(ctx context.Context, t *testing.T, config *Config) (snapshots.Snapshotter, func() error, error) {
+	// Create loopback devices for each test case
+	_, loopDataDevice := createLoopbackDevice(t, config.RootPath)
+	_, loopMetaDevice := createLoopbackDevice(t, config.RootPath)
+
+	err := dmsetup.CreatePool(config.PoolName, loopDataDevice, loopMetaDevice, 64*1024/dmsetup.SectorSize)
+	assert.NilError(t, err, "failed to create pool %q", config.PoolName)
+
+	snap, err := NewSnapshotter(ctx, config)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	// Remove device mapper pool and detach loop devices after test completes
+	removePool := func() error {
+		result := multierror.Append(
+			snap.pool.RemovePool(ctx),
+			mount.DetachLoopDevice(loopDataDevice, loopMetaDevice))
+
+		return result.ErrorOrNil()
+	}
+
+	// Pool cleanup should be called before closing metadata store (as we need to retrieve device names)
+	snap.cleanupFn = append([]closeFunc{removePool}, snap.cleanupFn...)
+
+	return snap, snap.Close, nil
+}