From 7beaa5e8594f088b97f637cc98a871c16634225c Mon Sep 17 00:00:00 2001
From: Derek McGowan <derek@mcg.dev>
Date: Tue, 23 May 2023 10:33:23 -0700
Subject: [PATCH] Add mount options to blockfile snapshotter

Signed-off-by: Derek McGowan <derek@mcg.dev>
---
 snapshots/blockfile/blockfile.go              | 23 +++++++++++++++----
 .../blockfile/blockfile_loopsetup_test.go     |  2 ++
 snapshots/blockfile/plugin/plugin.go          |  6 +++++
 3 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/snapshots/blockfile/blockfile.go b/snapshots/blockfile/blockfile.go
index 9886272e2..a504a62ef 100644
--- a/snapshots/blockfile/blockfile.go
+++ b/snapshots/blockfile/blockfile.go
@@ -41,6 +41,9 @@ type SnapshotterConfig struct {
 
 	// fsType is the filesystem type for the mount (defaults to ext4)
 	fsType string
+
+	// mountOptions are the base options added to the mount (defaults to ["loop"])
+	mountOptions []string
 }
 
 // Opt is an option to configure the overlay snapshotter
@@ -68,10 +71,19 @@ func WithFSType(fsType string) Opt {
 	}
 }
 
+// WithMountOptions defines the mount options used for the mount
+func WithMountOptions(options []string) Opt {
+	return func(root string, config *SnapshotterConfig) {
+		config.mountOptions = options
+	}
+
+}
+
 type snapshotter struct {
 	root    string
 	scratch string
 	fsType  string
+	options []string
 	ms      *storage.MetaStore
 }
 
@@ -110,6 +122,10 @@ func NewSnapshotter(root string, opts ...Opt) (snapshots.Snapshotter, error) {
 		config.fsType = "ext4"
 	}
 
+	if config.mountOptions != nil {
+		config.mountOptions = []string{"loop"}
+	}
+
 	ms, err := storage.NewMetaStore(filepath.Join(root, "metadata.db"))
 	if err != nil {
 		return nil, err
@@ -123,6 +139,7 @@ func NewSnapshotter(root string, opts ...Opt) (snapshots.Snapshotter, error) {
 		root:    root,
 		scratch: scratch,
 		fsType:  config.fsType,
+		options: config.mountOptions,
 		ms:      ms,
 	}, nil
 }
@@ -356,10 +373,8 @@ func (o *snapshotter) getBlockFile(id string) string {
 
 func (o *snapshotter) mounts(s storage.Snapshot) []mount.Mount {
 	var (
-		mountOptions = []string{
-			"loop",
-		}
-		source string
+		mountOptions = o.options
+		source       string
 	)
 
 	if s.Kind == snapshots.KindView {
diff --git a/snapshots/blockfile/blockfile_loopsetup_test.go b/snapshots/blockfile/blockfile_loopsetup_test.go
index 816f12ffd..06b4dd306 100644
--- a/snapshots/blockfile/blockfile_loopsetup_test.go
+++ b/snapshots/blockfile/blockfile_loopsetup_test.go
@@ -66,6 +66,8 @@ func setupSnapshotter(t *testing.T) ([]Opt, error) {
 
 	return []Opt{
 		WithScratchFile(scratch),
+		WithFSType("ext4"),
+		WithMountOptions([]string{"loop", "sync"}),
 	}, nil
 }
 
diff --git a/snapshots/blockfile/plugin/plugin.go b/snapshots/blockfile/plugin/plugin.go
index a3c0f0d52..8381537cf 100644
--- a/snapshots/blockfile/plugin/plugin.go
+++ b/snapshots/blockfile/plugin/plugin.go
@@ -34,6 +34,9 @@ type Config struct {
 
 	// FSType is the filesystem type for the mount
 	FSType string `toml:"fs_type"`
+
+	// MountOptions are options used for the mount
+	MountOptions []string `toml:"mount_options"`
 }
 
 func init() {
@@ -60,6 +63,9 @@ func init() {
 			if config.FSType != "" {
 				opts = append(opts, blockfile.WithFSType(config.FSType))
 			}
+			if len(config.MountOptions) > 0 {
+				opts = append(opts, blockfile.WithMountOptions(config.MountOptions))
+			}
 
 			return blockfile.NewSnapshotter(root, opts...)
 		},