Inline vfs.VirtualFilesystem in Kernel struct

This saves one pointer dereference per VFS access.

Updates #1623

PiperOrigin-RevId: 295216176

10 files changed, 43 insertions, 17 deletions

diff --git a/pkg/sentry/fsimpl/devtmpfs/devtmpfs_test.go b/pkg/sentry/fsimpl/devtmpfs/devtmpfs_test.go
index 73308a2b5..b6d52c015 100644
--- a/pkg/sentry/fsimpl/devtmpfs/devtmpfs_test.go
+++ b/pkg/sentry/fsimpl/devtmpfs/devtmpfs_test.go
@@ -29,7 +29,10 @@ func TestDevtmpfs(t *testing.T) {
 	ctx := contexttest.Context(t)
 	creds := auth.CredentialsFromContext(ctx)
 
-	vfsObj := vfs.New()
+	vfsObj := &vfs.VirtualFilesystem{}
+	if err := vfsObj.Init(); err != nil {
+		t.Fatalf("VFS init: %v", err)
+	}
 	// Register tmpfs just so that we can have a root filesystem that isn't
 	// devtmpfs.
 	vfsObj.MustRegisterFilesystemType("tmpfs", tmpfs.FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{
diff --git a/pkg/sentry/fsimpl/ext/benchmark/benchmark_test.go b/pkg/sentry/fsimpl/ext/benchmark/benchmark_test.go
index 2015a8871..89caee3df 100644
--- a/pkg/sentry/fsimpl/ext/benchmark/benchmark_test.go
+++ b/pkg/sentry/fsimpl/ext/benchmark/benchmark_test.go
@@ -52,7 +52,10 @@ func setUp(b *testing.B, imagePath string) (context.Context, *vfs.VirtualFilesys
 	creds := auth.CredentialsFromContext(ctx)
 
 	// Create VFS.
-	vfsObj := vfs.New()
+	vfsObj := &vfs.VirtualFilesystem{}
+	if err := vfsObj.Init(); err != nil {
+		return nil, nil, nil, nil, err
+	}
 	vfsObj.MustRegisterFilesystemType("extfs", ext.FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{
 		AllowUserMount: true,
 	})
diff --git a/pkg/sentry/fsimpl/ext/ext_test.go b/pkg/sentry/fsimpl/ext/ext_test.go
index 05f992826..ef6127f3c 100644
--- a/pkg/sentry/fsimpl/ext/ext_test.go
+++ b/pkg/sentry/fsimpl/ext/ext_test.go
@@ -65,7 +65,10 @@ func setUp(t *testing.T, imagePath string) (context.Context, *vfs.VirtualFilesys
 	creds := auth.CredentialsFromContext(ctx)
 
 	// Create VFS.
-	vfsObj := vfs.New()
+	vfsObj := &vfs.VirtualFilesystem{}
+	if err := vfsObj.Init(); err != nil {
+		t.Fatalf("VFS init: %v", err)
+	}
 	vfsObj.MustRegisterFilesystemType("extfs", FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{
 		AllowUserMount: true,
 	})
diff --git a/pkg/sentry/fsimpl/kernfs/kernfs_test.go b/pkg/sentry/fsimpl/kernfs/kernfs_test.go
index 96a16e654..0459fb305 100644
--- a/pkg/sentry/fsimpl/kernfs/kernfs_test.go
+++ b/pkg/sentry/fsimpl/kernfs/kernfs_test.go
@@ -45,7 +45,10 @@ type RootDentryFn func(*auth.Credentials, *filesystem) *kernfs.Dentry
 func newTestSystem(t *testing.T, rootFn RootDentryFn) *testutil.System {
 	ctx := contexttest.Context(t)
 	creds := auth.CredentialsFromContext(ctx)
-	v := vfs.New()
+	v := &vfs.VirtualFilesystem{}
+	if err := v.Init(); err != nil {
+		t.Fatalf("VFS init: %v", err)
+	}
 	v.MustRegisterFilesystemType("testfs", &fsType{rootFn: rootFn}, &vfs.RegisterFilesystemTypeOptions{
 		AllowUserMount: true,
 	})
diff --git a/pkg/sentry/fsimpl/proc/tasks_test.go b/pkg/sentry/fsimpl/proc/tasks_test.go
index 96c72cbc9..c5d531fe0 100644
--- a/pkg/sentry/fsimpl/proc/tasks_test.go
+++ b/pkg/sentry/fsimpl/proc/tasks_test.go
@@ -90,7 +90,7 @@ func setup(t *testing.T) *testutil.System {
 	ctx := k.SupervisorContext()
 	creds := auth.CredentialsFromContext(ctx)
 
-	k.VFS.MustRegisterFilesystemType(Name, &FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{
+	k.VFS().MustRegisterFilesystemType(Name, &FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{
 		AllowUserMount: true,
 	})
 	fsOpts := vfs.GetFilesystemOptions{
@@ -101,11 +101,11 @@ func setup(t *testing.T) *testutil.System {
 			},
 		},
 	}
-	mntns, err := k.VFS.NewMountNamespace(ctx, creds, "", Name, &fsOpts)
+	mntns, err := k.VFS().NewMountNamespace(ctx, creds, "", Name, &fsOpts)
 	if err != nil {
 		t.Fatalf("NewMountNamespace(): %v", err)
 	}
-	return testutil.NewSystem(ctx, t, k.VFS, mntns)
+	return testutil.NewSystem(ctx, t, k.VFS(), mntns)
 }
 
 func TestTasksEmpty(t *testing.T) {
diff --git a/pkg/sentry/fsimpl/sys/sys_test.go b/pkg/sentry/fsimpl/sys/sys_test.go
index 5d1ba5867..4b3602d47 100644
--- a/pkg/sentry/fsimpl/sys/sys_test.go
+++ b/pkg/sentry/fsimpl/sys/sys_test.go
@@ -34,15 +34,15 @@ func newTestSystem(t *testing.T) *testutil.System {
 	}
 	ctx := k.SupervisorContext()
 	creds := auth.CredentialsFromContext(ctx)
-	k.VFS.MustRegisterFilesystemType(sys.Name, sys.FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{
+	k.VFS().MustRegisterFilesystemType(sys.Name, sys.FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{
 		AllowUserMount: true,
 	})
 
-	mns, err := k.VFS.NewMountNamespace(ctx, creds, "", sys.Name, &vfs.GetFilesystemOptions{})
+	mns, err := k.VFS().NewMountNamespace(ctx, creds, "", sys.Name, &vfs.GetFilesystemOptions{})
 	if err != nil {
 		t.Fatalf("Failed to create new mount namespace: %v", err)
 	}
-	return testutil.NewSystem(ctx, t, k.VFS, mns)
+	return testutil.NewSystem(ctx, t, k.VFS(), mns)
 }
 
 func TestReadCPUFile(t *testing.T) {
diff --git a/pkg/sentry/fsimpl/testutil/kernel.go b/pkg/sentry/fsimpl/testutil/kernel.go
index a91b3ec4d..d0be32e72 100644
--- a/pkg/sentry/fsimpl/testutil/kernel.go
+++ b/pkg/sentry/fsimpl/testutil/kernel.go
@@ -102,12 +102,13 @@ func Boot() (*kernel.Kernel, error) {
 
 	kernel.VFS2Enabled = true
 
-	vfsObj := vfs.New()
-	vfsObj.MustRegisterFilesystemType(tmpfs.Name, &tmpfs.FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{
+	if err := k.VFS().Init(); err != nil {
+		return nil, fmt.Errorf("VFS init: %v", err)
+	}
+	k.VFS().MustRegisterFilesystemType(tmpfs.Name, &tmpfs.FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{
 		AllowUserMount: true,
 		AllowUserList:  true,
 	})
-	k.VFS = vfsObj
 
 	ls, err := limits.NewLinuxLimitSet()
 	if err != nil {
diff --git a/pkg/sentry/fsimpl/tmpfs/benchmark_test.go b/pkg/sentry/fsimpl/tmpfs/benchmark_test.go
index 9fce5e4b4..383133e44 100644
--- a/pkg/sentry/fsimpl/tmpfs/benchmark_test.go
+++ b/pkg/sentry/fsimpl/tmpfs/benchmark_test.go
@@ -175,7 +175,10 @@ func BenchmarkVFS2MemfsStat(b *testing.B) {
 			creds := auth.CredentialsFromContext(ctx)
 
 			// Create VFS.
-			vfsObj := vfs.New()
+			vfsObj := vfs.VirtualFilesystem{}
+			if err := vfsObj.Init(); err != nil {
+				b.Fatalf("VFS init: %v", err)
+			}
 			vfsObj.MustRegisterFilesystemType("tmpfs", tmpfs.FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{
 				AllowUserMount: true,
 			})
@@ -366,7 +369,10 @@ func BenchmarkVFS2MemfsMountStat(b *testing.B) {
 			creds := auth.CredentialsFromContext(ctx)
 
 			// Create VFS.
-			vfsObj := vfs.New()
+			vfsObj := vfs.VirtualFilesystem{}
+			if err := vfsObj.Init(); err != nil {
+				b.Fatalf("VFS init: %v", err)
+			}
 			vfsObj.MustRegisterFilesystemType("tmpfs", tmpfs.FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{
 				AllowUserMount: true,
 			})
diff --git a/pkg/sentry/fsimpl/tmpfs/pipe_test.go b/pkg/sentry/fsimpl/tmpfs/pipe_test.go
index 5ee7f2a72..1614f2c39 100644
--- a/pkg/sentry/fsimpl/tmpfs/pipe_test.go
+++ b/pkg/sentry/fsimpl/tmpfs/pipe_test.go
@@ -151,7 +151,10 @@ func setup(t *testing.T) (context.Context, *auth.Credentials, *vfs.VirtualFilesy
 	creds := auth.CredentialsFromContext(ctx)
 
 	// Create VFS.
-	vfsObj := vfs.New()
+	vfsObj := &vfs.VirtualFilesystem{}
+	if err := vfsObj.Init(); err != nil {
+		t.Fatalf("VFS init: %v", err)
+	}
 	vfsObj.MustRegisterFilesystemType("tmpfs", FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{
 		AllowUserMount: true,
 	})
diff --git a/pkg/sentry/fsimpl/tmpfs/regular_file_test.go b/pkg/sentry/fsimpl/tmpfs/regular_file_test.go
index e9f71e334..0399725cf 100644
--- a/pkg/sentry/fsimpl/tmpfs/regular_file_test.go
+++ b/pkg/sentry/fsimpl/tmpfs/regular_file_test.go
@@ -40,7 +40,11 @@ var nextFileID int64
 func newTmpfsRoot(ctx context.Context) (*vfs.VirtualFilesystem, vfs.VirtualDentry, func(), error) {
 	creds := auth.CredentialsFromContext(ctx)
 
-	vfsObj := vfs.New()
+	vfsObj := &vfs.VirtualFilesystem{}
+	if err := vfsObj.Init(); err != nil {
+		return nil, vfs.VirtualDentry{}, nil, fmt.Errorf("VFS init: %v", err)
+	}
+
 	vfsObj.MustRegisterFilesystemType("tmpfs", FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{
 		AllowUserMount: true,
 	})