Merge release-20200818.0-132-gc8f1ce288 (automated)

34 files changed, 134 insertions, 87 deletions

diff --git a/pkg/abi/linux/linux_abi_autogen_unsafe.go b/pkg/abi/linux/linux_abi_autogen_unsafe.go
index 53d9f0796..790bf2428 100644
--- a/pkg/abi/linux/linux_abi_autogen_unsafe.go
+++ b/pkg/abi/linux/linux_abi_autogen_unsafe.go
@@ -155,12 +155,12 @@ func (s *Statx) UnmarshalBytes(src []byte) {
 // Packed implements marshal.Marshallable.Packed.
 //go:nosplit
 func (s *Statx) Packed() bool {
-    return s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() && s.Atime.Packed()
+    return s.Mtime.Packed() && s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed()
 }
 
 // MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
 func (s *Statx) MarshalUnsafe(dst []byte) {
-    if s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() {
+    if s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() && s.Atime.Packed() {
         safecopy.CopyIn(dst, unsafe.Pointer(s))
     } else {
         // Type Statx doesn't have a packed layout in memory, fallback to MarshalBytes.
@@ -181,7 +181,7 @@ func (s *Statx) UnmarshalUnsafe(src []byte) {
 // CopyOutN implements marshal.Marshallable.CopyOutN.
 //go:nosplit
 func (s *Statx) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {
-    if !s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() {
+    if !s.Ctime.Packed() && s.Mtime.Packed() && s.Atime.Packed() && s.Btime.Packed() {
         // Type Statx doesn't have a packed layout in memory, fall back to MarshalBytes.
         buf := task.CopyScratchBuffer(s.SizeBytes()) // escapes: okay.
         s.MarshalBytes(buf) // escapes: fallback.
@@ -211,7 +211,7 @@ func (s *Statx) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {
 // CopyIn implements marshal.Marshallable.CopyIn.
 //go:nosplit
 func (s *Statx) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
-    if !s.Mtime.Packed() && s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() {
+    if !s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() {
         // Type Statx doesn't have a packed layout in memory, fall back to UnmarshalBytes.
         buf := task.CopyScratchBuffer(s.SizeBytes()) // escapes: okay.
         length, err := task.CopyInBytes(addr, buf) // escapes: okay.
@@ -2023,7 +2023,7 @@ func (i *IPTEntry) UnmarshalBytes(src []byte) {
 // Packed implements marshal.Marshallable.Packed.
 //go:nosplit
 func (i *IPTEntry) Packed() bool {
-    return i.IP.Packed() && i.Counters.Packed()
+    return i.Counters.Packed() && i.IP.Packed()
 }
 
 // MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
@@ -2079,7 +2079,7 @@ func (i *IPTEntry) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {
 // CopyIn implements marshal.Marshallable.CopyIn.
 //go:nosplit
 func (i *IPTEntry) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
-    if !i.Counters.Packed() && i.IP.Packed() {
+    if !i.IP.Packed() && i.Counters.Packed() {
         // Type IPTEntry doesn't have a packed layout in memory, fall back to UnmarshalBytes.
         buf := task.CopyScratchBuffer(i.SizeBytes()) // escapes: okay.
         length, err := task.CopyInBytes(addr, buf) // escapes: okay.
@@ -2237,7 +2237,7 @@ func (i *IPTIP) UnmarshalUnsafe(src []byte) {
 // CopyOutN implements marshal.Marshallable.CopyOutN.
 //go:nosplit
 func (i *IPTIP) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {
-    if !i.DstMask.Packed() && i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() {
+    if !i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() {
         // Type IPTIP doesn't have a packed layout in memory, fall back to MarshalBytes.
         buf := task.CopyScratchBuffer(i.SizeBytes()) // escapes: okay.
         i.MarshalBytes(buf) // escapes: fallback.
@@ -2293,7 +2293,7 @@ func (i *IPTIP) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
 
 // WriteTo implements io.WriterTo.WriteTo.
 func (i *IPTIP) WriteTo(writer io.Writer) (int64, error) {
-    if !i.SrcMask.Packed() && i.DstMask.Packed() && i.Src.Packed() && i.Dst.Packed() {
+    if !i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() {
         // Type IPTIP doesn't have a packed layout in memory, fall back to MarshalBytes.
         buf := make([]byte, i.SizeBytes())
         i.MarshalBytes(buf)
@@ -3214,7 +3214,7 @@ func (i *IP6TIP) MarshalUnsafe(dst []byte) {
 
 // UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe.
 func (i *IP6TIP) UnmarshalUnsafe(src []byte) {
-    if i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() {
+    if i.SrcMask.Packed() && i.DstMask.Packed() && i.Src.Packed() && i.Dst.Packed() {
         safecopy.CopyOut(unsafe.Pointer(i), src)
     } else {
         // Type IP6TIP doesn't have a packed layout in memory, fallback to UnmarshalBytes.
@@ -3225,7 +3225,7 @@ func (i *IP6TIP) UnmarshalUnsafe(src []byte) {
 // CopyOutN implements marshal.Marshallable.CopyOutN.
 //go:nosplit
 func (i *IP6TIP) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {
-    if !i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() {
+    if !i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() && i.Src.Packed() {
         // Type IP6TIP doesn't have a packed layout in memory, fall back to MarshalBytes.
         buf := task.CopyScratchBuffer(i.SizeBytes()) // escapes: okay.
         i.MarshalBytes(buf) // escapes: fallback.
@@ -3255,7 +3255,7 @@ func (i *IP6TIP) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {
 // CopyIn implements marshal.Marshallable.CopyIn.
 //go:nosplit
 func (i *IP6TIP) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
-    if !i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() && i.Src.Packed() {
+    if !i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() {
         // Type IP6TIP doesn't have a packed layout in memory, fall back to UnmarshalBytes.
         buf := task.CopyScratchBuffer(i.SizeBytes()) // escapes: okay.
         length, err := task.CopyInBytes(addr, buf) // escapes: okay.
@@ -3281,7 +3281,7 @@ func (i *IP6TIP) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
 
 // WriteTo implements io.WriterTo.WriteTo.
 func (i *IP6TIP) WriteTo(writer io.Writer) (int64, error) {
-    if !i.DstMask.Packed() && i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() {
+    if !i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() {
         // Type IP6TIP doesn't have a packed layout in memory, fall back to MarshalBytes.
         buf := make([]byte, i.SizeBytes())
         i.MarshalBytes(buf)
diff --git a/pkg/abi/linux/linux_amd64_abi_autogen_unsafe.go b/pkg/abi/linux/linux_amd64_abi_autogen_unsafe.go
index 41b6f2499..c0e6a5d70 100644
--- a/pkg/abi/linux/linux_amd64_abi_autogen_unsafe.go
+++ b/pkg/abi/linux/linux_amd64_abi_autogen_unsafe.go
@@ -288,7 +288,7 @@ func (s *Stat) UnmarshalBytes(src []byte) {
 // Packed implements marshal.Marshallable.Packed.
 //go:nosplit
 func (s *Stat) Packed() bool {
-    return s.ATime.Packed() && s.MTime.Packed() && s.CTime.Packed()
+    return s.CTime.Packed() && s.ATime.Packed() && s.MTime.Packed()
 }
 
 // MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
@@ -314,7 +314,7 @@ func (s *Stat) UnmarshalUnsafe(src []byte) {
 // CopyOutN implements marshal.Marshallable.CopyOutN.
 //go:nosplit
 func (s *Stat) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {
-    if !s.ATime.Packed() && s.MTime.Packed() && s.CTime.Packed() {
+    if !s.CTime.Packed() && s.ATime.Packed() && s.MTime.Packed() {
         // Type Stat doesn't have a packed layout in memory, fall back to MarshalBytes.
         buf := task.CopyScratchBuffer(s.SizeBytes()) // escapes: okay.
         s.MarshalBytes(buf) // escapes: fallback.
@@ -344,7 +344,7 @@ func (s *Stat) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {
 // CopyIn implements marshal.Marshallable.CopyIn.
 //go:nosplit
 func (s *Stat) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
-    if !s.ATime.Packed() && s.MTime.Packed() && s.CTime.Packed() {
+    if !s.MTime.Packed() && s.CTime.Packed() && s.ATime.Packed() {
         // Type Stat doesn't have a packed layout in memory, fall back to UnmarshalBytes.
         buf := task.CopyScratchBuffer(s.SizeBytes()) // escapes: okay.
         length, err := task.CopyInBytes(addr, buf) // escapes: okay.
diff --git a/pkg/abi/linux/linux_arm64_abi_autogen_unsafe.go b/pkg/abi/linux/linux_arm64_abi_autogen_unsafe.go
index 7c3d244b0..311ecd388 100644
--- a/pkg/abi/linux/linux_arm64_abi_autogen_unsafe.go
+++ b/pkg/abi/linux/linux_arm64_abi_autogen_unsafe.go
@@ -300,7 +300,7 @@ func (s *Stat) Packed() bool {
 
 // MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
 func (s *Stat) MarshalUnsafe(dst []byte) {
-    if s.CTime.Packed() && s.ATime.Packed() && s.MTime.Packed() {
+    if s.ATime.Packed() && s.MTime.Packed() && s.CTime.Packed() {
         safecopy.CopyIn(dst, unsafe.Pointer(s))
     } else {
         // Type Stat doesn't have a packed layout in memory, fallback to MarshalBytes.
@@ -310,7 +310,7 @@ func (s *Stat) MarshalUnsafe(dst []byte) {
 
 // UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe.
 func (s *Stat) UnmarshalUnsafe(src []byte) {
-    if s.ATime.Packed() && s.MTime.Packed() && s.CTime.Packed() {
+    if s.MTime.Packed() && s.CTime.Packed() && s.ATime.Packed() {
         safecopy.CopyOut(unsafe.Pointer(s), src)
     } else {
         // Type Stat doesn't have a packed layout in memory, fallback to UnmarshalBytes.
@@ -321,7 +321,7 @@ func (s *Stat) UnmarshalUnsafe(src []byte) {
 // CopyOutN implements marshal.Marshallable.CopyOutN.
 //go:nosplit
 func (s *Stat) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {
-    if !s.MTime.Packed() && s.CTime.Packed() && s.ATime.Packed() {
+    if !s.CTime.Packed() && s.ATime.Packed() && s.MTime.Packed() {
         // Type Stat doesn't have a packed layout in memory, fall back to MarshalBytes.
         buf := task.CopyScratchBuffer(s.SizeBytes()) // escapes: okay.
         s.MarshalBytes(buf) // escapes: fallback.
diff --git a/pkg/sentry/fsimpl/devpts/root_inode_refs.go b/pkg/sentry/fsimpl/devpts/root_inode_refs.go
index 4abb66431..051801202 100644
--- a/pkg/sentry/fsimpl/devpts/root_inode_refs.go
+++ b/pkg/sentry/fsimpl/devpts/root_inode_refs.go
@@ -2,10 +2,11 @@ package devpts
 
 import (
 	"fmt"
-	"gvisor.dev/gvisor/pkg/log"
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 	"runtime"
 	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/fsimpl/devtmpfs/devtmpfs.go b/pkg/sentry/fsimpl/devtmpfs/devtmpfs.go
index 52f44f66d..a23094e54 100644
--- a/pkg/sentry/fsimpl/devtmpfs/devtmpfs.go
+++ b/pkg/sentry/fsimpl/devtmpfs/devtmpfs.go
@@ -80,7 +80,7 @@ type Accessor struct {
 // NewAccessor returns an Accessor that supports creation of device special
 // files in the devtmpfs instance registered with name fsTypeName in vfsObj.
 func NewAccessor(ctx context.Context, vfsObj *vfs.VirtualFilesystem, creds *auth.Credentials, fsTypeName string) (*Accessor, error) {
-	mntns, err := vfsObj.NewMountNamespace(ctx, creds, "devtmpfs" /* source */, fsTypeName, &vfs.GetFilesystemOptions{})
+	mntns, err := vfsObj.NewMountNamespace(ctx, creds, "devtmpfs" /* source */, fsTypeName, &vfs.MountOptions{})
 	if err != nil {
 		return nil, err
 	}
diff --git a/pkg/sentry/fsimpl/fuse/inode_refs.go b/pkg/sentry/fsimpl/fuse/inode_refs.go
index 4fb4d4da7..6b9456e1d 100644
--- a/pkg/sentry/fsimpl/fuse/inode_refs.go
+++ b/pkg/sentry/fsimpl/fuse/inode_refs.go
@@ -2,10 +2,11 @@ package fuse
 
 import (
 	"fmt"
-	"gvisor.dev/gvisor/pkg/log"
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 	"runtime"
 	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/fsimpl/host/connected_endpoint_refs.go b/pkg/sentry/fsimpl/host/connected_endpoint_refs.go
index 225f59782..babb3f664 100644
--- a/pkg/sentry/fsimpl/host/connected_endpoint_refs.go
+++ b/pkg/sentry/fsimpl/host/connected_endpoint_refs.go
@@ -2,10 +2,11 @@ package host
 
 import (
 	"fmt"
-	"gvisor.dev/gvisor/pkg/log"
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 	"runtime"
 	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/fsimpl/host/inode_refs.go b/pkg/sentry/fsimpl/host/inode_refs.go
index 4075eae17..17f90ce4a 100644
--- a/pkg/sentry/fsimpl/host/inode_refs.go
+++ b/pkg/sentry/fsimpl/host/inode_refs.go
@@ -2,10 +2,11 @@ package host
 
 import (
 	"fmt"
-	"gvisor.dev/gvisor/pkg/log"
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 	"runtime"
 	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/fsimpl/kernfs/dentry_refs.go b/pkg/sentry/fsimpl/kernfs/dentry_refs.go
index f99d4941a..79863b3bc 100644
--- a/pkg/sentry/fsimpl/kernfs/dentry_refs.go
+++ b/pkg/sentry/fsimpl/kernfs/dentry_refs.go
@@ -2,10 +2,11 @@ package kernfs
 
 import (
 	"fmt"
-	"gvisor.dev/gvisor/pkg/log"
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 	"runtime"
 	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/fsimpl/kernfs/static_directory_refs.go b/pkg/sentry/fsimpl/kernfs/static_directory_refs.go
index 2b258010e..478b04bdd 100644
--- a/pkg/sentry/fsimpl/kernfs/static_directory_refs.go
+++ b/pkg/sentry/fsimpl/kernfs/static_directory_refs.go
@@ -2,10 +2,11 @@ package kernfs
 
 import (
 	"fmt"
-	"gvisor.dev/gvisor/pkg/log"
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 	"runtime"
 	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/fsimpl/proc/fd_dir_inode_refs.go b/pkg/sentry/fsimpl/proc/fd_dir_inode_refs.go
index 467c32752..9431c1506 100644
--- a/pkg/sentry/fsimpl/proc/fd_dir_inode_refs.go
+++ b/pkg/sentry/fsimpl/proc/fd_dir_inode_refs.go
@@ -2,10 +2,11 @@ package proc
 
 import (
 	"fmt"
-	"gvisor.dev/gvisor/pkg/log"
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 	"runtime"
 	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/fsimpl/proc/fd_info_dir_inode_refs.go b/pkg/sentry/fsimpl/proc/fd_info_dir_inode_refs.go
index 3fcda0948..872b20eb0 100644
--- a/pkg/sentry/fsimpl/proc/fd_info_dir_inode_refs.go
+++ b/pkg/sentry/fsimpl/proc/fd_info_dir_inode_refs.go
@@ -2,10 +2,11 @@ package proc
 
 import (
 	"fmt"
-	"gvisor.dev/gvisor/pkg/log"
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 	"runtime"
 	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/fsimpl/proc/subtasks_inode_refs.go b/pkg/sentry/fsimpl/proc/subtasks_inode_refs.go
index 2da6801c2..c6d9b3522 100644
--- a/pkg/sentry/fsimpl/proc/subtasks_inode_refs.go
+++ b/pkg/sentry/fsimpl/proc/subtasks_inode_refs.go
@@ -2,10 +2,11 @@ package proc
 
 import (
 	"fmt"
-	"gvisor.dev/gvisor/pkg/log"
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 	"runtime"
 	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/fsimpl/proc/task_inode_refs.go b/pkg/sentry/fsimpl/proc/task_inode_refs.go
index b6e19844c..714488450 100644
--- a/pkg/sentry/fsimpl/proc/task_inode_refs.go
+++ b/pkg/sentry/fsimpl/proc/task_inode_refs.go
@@ -2,10 +2,11 @@ package proc
 
 import (
 	"fmt"
-	"gvisor.dev/gvisor/pkg/log"
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 	"runtime"
 	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/fsimpl/proc/tasks_inode_refs.go b/pkg/sentry/fsimpl/proc/tasks_inode_refs.go
index 6207364e4..22d9cc488 100644
--- a/pkg/sentry/fsimpl/proc/tasks_inode_refs.go
+++ b/pkg/sentry/fsimpl/proc/tasks_inode_refs.go
@@ -2,10 +2,11 @@ package proc
 
 import (
 	"fmt"
-	"gvisor.dev/gvisor/pkg/log"
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 	"runtime"
 	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/fsimpl/sys/dir_refs.go b/pkg/sentry/fsimpl/sys/dir_refs.go
index 9d15d4c80..89609b198 100644
--- a/pkg/sentry/fsimpl/sys/dir_refs.go
+++ b/pkg/sentry/fsimpl/sys/dir_refs.go
@@ -2,10 +2,11 @@ package sys
 
 import (
 	"fmt"
-	"gvisor.dev/gvisor/pkg/log"
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 	"runtime"
 	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/fsimpl/tmpfs/inode_refs.go b/pkg/sentry/fsimpl/tmpfs/inode_refs.go
index ff5e99c52..dbf0b2766 100644
--- a/pkg/sentry/fsimpl/tmpfs/inode_refs.go
+++ b/pkg/sentry/fsimpl/tmpfs/inode_refs.go
@@ -2,10 +2,11 @@ package tmpfs
 
 import (
 	"fmt"
-	"gvisor.dev/gvisor/pkg/log"
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 	"runtime"
 	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/kernel/fd_table_refs.go b/pkg/sentry/kernel/fd_table_refs.go
index a630289c9..ecba138ac 100644
--- a/pkg/sentry/kernel/fd_table_refs.go
+++ b/pkg/sentry/kernel/fd_table_refs.go
@@ -2,10 +2,11 @@ package kernel
 
 import (
 	"fmt"
-	"gvisor.dev/gvisor/pkg/log"
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 	"runtime"
 	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/kernel/fs_context_refs.go b/pkg/sentry/kernel/fs_context_refs.go
index e8bb1e6ee..fb2fde971 100644
--- a/pkg/sentry/kernel/fs_context_refs.go
+++ b/pkg/sentry/kernel/fs_context_refs.go
@@ -2,10 +2,11 @@ package kernel
 
 import (
 	"fmt"
-	"gvisor.dev/gvisor/pkg/log"
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 	"runtime"
 	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/kernel/process_group_refs.go b/pkg/sentry/kernel/process_group_refs.go
index 4b257d548..4ed6e6458 100644
--- a/pkg/sentry/kernel/process_group_refs.go
+++ b/pkg/sentry/kernel/process_group_refs.go
@@ -2,10 +2,11 @@ package kernel
 
 import (
 	"fmt"
-	"gvisor.dev/gvisor/pkg/log"
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 	"runtime"
 	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/kernel/session_refs.go b/pkg/sentry/kernel/session_refs.go
index 204fdd060..f2e1bb797 100644
--- a/pkg/sentry/kernel/session_refs.go
+++ b/pkg/sentry/kernel/session_refs.go
@@ -2,10 +2,11 @@ package kernel
 
 import (
 	"fmt"
-	"gvisor.dev/gvisor/pkg/log"
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 	"runtime"
 	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/kernel/shm/shm_refs.go b/pkg/sentry/kernel/shm/shm_refs.go
index 4bffdd0b3..51e07d0b3 100644
--- a/pkg/sentry/kernel/shm/shm_refs.go
+++ b/pkg/sentry/kernel/shm/shm_refs.go
@@ -2,10 +2,11 @@ package shm
 
 import (
 	"fmt"
-	"gvisor.dev/gvisor/pkg/log"
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 	"runtime"
 	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/mm/aio_mappable_refs.go b/pkg/sentry/mm/aio_mappable_refs.go
index 141747137..b99909f07 100644
--- a/pkg/sentry/mm/aio_mappable_refs.go
+++ b/pkg/sentry/mm/aio_mappable_refs.go
@@ -2,10 +2,11 @@ package mm
 
 import (
 	"fmt"
-	"gvisor.dev/gvisor/pkg/log"
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 	"runtime"
 	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/mm/special_mappable_refs.go b/pkg/sentry/mm/special_mappable_refs.go
index 0921a5d18..035bbe690 100644
--- a/pkg/sentry/mm/special_mappable_refs.go
+++ b/pkg/sentry/mm/special_mappable_refs.go
@@ -2,10 +2,11 @@ package mm
 
 import (
 	"fmt"
-	"gvisor.dev/gvisor/pkg/log"
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 	"runtime"
 	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/platform/ring0/defs_impl_arm64.go b/pkg/sentry/platform/ring0/defs_impl_arm64.go
index 424b66f76..eba2eac30 100644
--- a/pkg/sentry/platform/ring0/defs_impl_arm64.go
+++ b/pkg/sentry/platform/ring0/defs_impl_arm64.go
@@ -3,11 +3,11 @@ package ring0
 import (
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
+	"io"
+	"reflect"
 
 	"fmt"
 	"gvisor.dev/gvisor/pkg/usermem"
-	"io"
-	"reflect"
 )
 
 // Useful bits.
diff --git a/pkg/sentry/socket/unix/socket_refs.go b/pkg/sentry/socket/unix/socket_refs.go
index 39aaedc7f..dababb85f 100644
--- a/pkg/sentry/socket/unix/socket_refs.go
+++ b/pkg/sentry/socket/unix/socket_refs.go
@@ -2,10 +2,11 @@ package unix
 
 import (
 	"fmt"
-	"gvisor.dev/gvisor/pkg/log"
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 	"runtime"
 	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/socket/unix/transport/queue_refs.go b/pkg/sentry/socket/unix/transport/queue_refs.go
index 4c3dcd13f..0d4e34988 100644
--- a/pkg/sentry/socket/unix/transport/queue_refs.go
+++ b/pkg/sentry/socket/unix/transport/queue_refs.go
@@ -2,10 +2,11 @@ package transport
 
 import (
 	"fmt"
-	"gvisor.dev/gvisor/pkg/log"
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 	"runtime"
 	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/vfs/file_description_refs.go b/pkg/sentry/vfs/file_description_refs.go
index 6c7747259..bdd7e6554 100644
--- a/pkg/sentry/vfs/file_description_refs.go
+++ b/pkg/sentry/vfs/file_description_refs.go
@@ -2,10 +2,11 @@ package vfs
 
 import (
 	"fmt"
-	"gvisor.dev/gvisor/pkg/log"
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 	"runtime"
 	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/vfs/filesystem_refs.go b/pkg/sentry/vfs/filesystem_refs.go
index 96f681831..38a9a986f 100644
--- a/pkg/sentry/vfs/filesystem_refs.go
+++ b/pkg/sentry/vfs/filesystem_refs.go
@@ -2,10 +2,11 @@ package vfs
 
 import (
 	"fmt"
-	"gvisor.dev/gvisor/pkg/log"
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 	"runtime"
 	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/vfs/mount.go b/pkg/sentry/vfs/mount.go
index db5fb3bb1..06ca91989 100644
--- a/pkg/sentry/vfs/mount.go
+++ b/pkg/sentry/vfs/mount.go
@@ -154,13 +154,13 @@ type MountNamespace struct {
 // NewMountNamespace returns a new mount namespace with a root filesystem
 // configured by the given arguments. A reference is taken on the returned
 // MountNamespace.
-func (vfs *VirtualFilesystem) NewMountNamespace(ctx context.Context, creds *auth.Credentials, source, fsTypeName string, opts *GetFilesystemOptions) (*MountNamespace, error) {
+func (vfs *VirtualFilesystem) NewMountNamespace(ctx context.Context, creds *auth.Credentials, source, fsTypeName string, opts *MountOptions) (*MountNamespace, error) {
 	rft := vfs.getFilesystemType(fsTypeName)
 	if rft == nil {
 		ctx.Warningf("Unknown filesystem type: %s", fsTypeName)
 		return nil, syserror.ENODEV
 	}
-	fs, root, err := rft.fsType.GetFilesystem(ctx, vfs, creds, source, *opts)
+	fs, root, err := rft.fsType.GetFilesystem(ctx, vfs, creds, source, opts.GetFilesystemOptions)
 	if err != nil {
 		return nil, err
 	}
@@ -169,7 +169,7 @@ func (vfs *VirtualFilesystem) NewMountNamespace(ctx context.Context, creds *auth
 		mountpoints: make(map[*Dentry]uint32),
 	}
 	mntns.EnableLeakCheck()
-	mntns.root = newMount(vfs, fs, root, mntns, &MountOptions{})
+	mntns.root = newMount(vfs, fs, root, mntns, opts)
 	return mntns, nil
 }
 
diff --git a/pkg/sentry/vfs/mount_namespace_refs.go b/pkg/sentry/vfs/mount_namespace_refs.go
index 4c422c81f..63285fb8e 100644
--- a/pkg/sentry/vfs/mount_namespace_refs.go
+++ b/pkg/sentry/vfs/mount_namespace_refs.go
@@ -2,10 +2,11 @@ package vfs
 
 import (
 	"fmt"
-	"gvisor.dev/gvisor/pkg/log"
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 	"runtime"
 	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/tcpip/link/tun/tun_endpoint_refs.go b/pkg/tcpip/link/tun/tun_endpoint_refs.go
index 9a38142f5..e0595429c 100644
--- a/pkg/tcpip/link/tun/tun_endpoint_refs.go
+++ b/pkg/tcpip/link/tun/tun_endpoint_refs.go
@@ -2,10 +2,11 @@ package tun
 
 import (
 	"fmt"
-	"gvisor.dev/gvisor/pkg/log"
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 	"runtime"
 	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/runsc/boot/fs.go b/runsc/boot/fs.go
index e2c5f5fb1..ddf288456 100644
--- a/runsc/boot/fs.go
+++ b/runsc/boot/fs.go
@@ -254,7 +254,7 @@ func mustFindFilesystem(name string) fs.Filesystem {
 
 // addSubmountOverlay overlays the inode over a ramfs tree containing the given
 // paths.
-func addSubmountOverlay(ctx context.Context, inode *fs.Inode, submounts []string) (*fs.Inode, error) {
+func addSubmountOverlay(ctx context.Context, inode *fs.Inode, submounts []string, mf fs.MountSourceFlags) (*fs.Inode, error) {
 	// Construct a ramfs tree of mount points. The contents never
 	// change, so this can be fully caching. There's no real
 	// filesystem backing this tree, so we set the filesystem to
@@ -264,7 +264,7 @@ func addSubmountOverlay(ctx context.Context, inode *fs.Inode, submounts []string
 	if err != nil {
 		return nil, fmt.Errorf("creating mount tree: %v", err)
 	}
-	overlayInode, err := fs.NewOverlayRoot(ctx, inode, mountTree, fs.MountSourceFlags{})
+	overlayInode, err := fs.NewOverlayRoot(ctx, inode, mountTree, mf)
 	if err != nil {
 		return nil, fmt.Errorf("adding mount overlay: %v", err)
 	}
@@ -741,7 +741,7 @@ func (c *containerMounter) createRootMount(ctx context.Context, conf *config.Con
 	// for submount paths.  "/dev" "/sys" "/proc" and "/tmp" are always
 	// mounted even if they are not in the spec.
 	submounts := append(subtargets("/", c.mounts), "/dev", "/sys", "/proc", "/tmp")
-	rootInode, err = addSubmountOverlay(ctx, rootInode, submounts)
+	rootInode, err = addSubmountOverlay(ctx, rootInode, submounts, mf)
 	if err != nil {
 		return nil, fmt.Errorf("adding submount overlay: %v", err)
 	}
@@ -851,7 +851,7 @@ func (c *containerMounter) mountSubmount(ctx context.Context, conf *config.Confi
 	submounts := subtargets(m.Destination, c.mounts)
 	if len(submounts) > 0 {
 		log.Infof("Adding submount overlay over %q", m.Destination)
-		inode, err = addSubmountOverlay(ctx, inode, submounts)
+		inode, err = addSubmountOverlay(ctx, inode, submounts, mf)
 		if err != nil {
 			return fmt.Errorf("adding submount overlay: %v", err)
 		}
diff --git a/runsc/boot/vfs.go b/runsc/boot/vfs.go
index 66b6cf19b..7844ea28c 100644
--- a/runsc/boot/vfs.go
+++ b/runsc/boot/vfs.go
@@ -134,7 +134,7 @@ func registerFilesystems(k *kernel.Kernel) error {
 }
 
 func setupContainerVFS2(ctx context.Context, conf *config.Config, mntr *containerMounter, procArgs *kernel.CreateProcessArgs) error {
-	mns, err := mntr.setupVFS2(ctx, conf, procArgs)
+	mns, err := mntr.mountAll(conf, procArgs)
 	if err != nil {
 		return fmt.Errorf("failed to setupFS: %w", err)
 	}
@@ -149,7 +149,7 @@ func setupContainerVFS2(ctx context.Context, conf *config.Config, mntr *containe
 	return nil
 }
 
-func (c *containerMounter) setupVFS2(ctx context.Context, conf *config.Config, procArgs *kernel.CreateProcessArgs) (*vfs.MountNamespace, error) {
+func (c *containerMounter) mountAll(conf *config.Config, procArgs *kernel.CreateProcessArgs) (*vfs.MountNamespace, error) {
 	log.Infof("Configuring container's file system with VFS2")
 
 	// Create context with root credentials to mount the filesystem (the current
@@ -172,24 +172,44 @@ func (c *containerMounter) setupVFS2(ctx context.Context, conf *config.Config, p
 	if err := c.mountSubmountsVFS2(rootCtx, conf, mns, rootCreds); err != nil {
 		return nil, fmt.Errorf("mounting submounts vfs2: %w", err)
 	}
+
+	if c.root.Readonly || conf.Overlay {
+		// Switch to ReadOnly after all submounts were setup.
+		root := mns.Root()
+		defer root.DecRef(rootCtx)
+		if err := c.k.VFS().SetMountReadOnly(root.Mount(), true); err != nil {
+			return nil, fmt.Errorf(`failed to set mount at "/" readonly: %v`, err)
+		}
+	}
+
 	return mns, nil
 }
 
+// createMountNamespaceVFS2 creates the container's root mount and namespace.
+// The mount is created ReadWrite to allow mount point for submounts to be
+// created. ** The caller is responsible to switch to ReadOnly if needed **
 func (c *containerMounter) createMountNamespaceVFS2(ctx context.Context, conf *config.Config, creds *auth.Credentials) (*vfs.MountNamespace, error) {
 	fd := c.fds.remove()
-	opts := p9MountData(fd, conf.FileAccess, true /* vfs2 */)
+	data := p9MountData(fd, conf.FileAccess, true /* vfs2 */)
 
 	if conf.OverlayfsStaleRead {
 		// We can't check for overlayfs here because sandbox is chroot'ed and gofer
 		// can only send mount options for specs.Mounts (specs.Root is missing
 		// Options field). So assume root is always on top of overlayfs.
-		opts = append(opts, "overlayfs_stale_read")
+		data = append(data, "overlayfs_stale_read")
 	}
 
 	log.Infof("Mounting root over 9P, ioFD: %d", fd)
-	mns, err := c.k.VFS().NewMountNamespace(ctx, creds, "", gofer.Name, &vfs.GetFilesystemOptions{
-		Data: strings.Join(opts, ","),
-	})
+	opts := &vfs.MountOptions{
+		// Always mount as ReadWrite to allow other mounts on top of it. It'll be
+		// made ReadOnly in the caller (if needed).
+		ReadOnly: false,
+		GetFilesystemOptions: vfs.GetFilesystemOptions{
+			Data: strings.Join(data, ","),
+		},
+		InternalMount: true,
+	}
+	mns, err := c.k.VFS().NewMountNamespace(ctx, creds, "", gofer.Name, opts)
 	if err != nil {
 		return nil, fmt.Errorf("setting up mount namespace: %w", err)
 	}
@@ -227,6 +247,7 @@ func (c *containerMounter) mountSubmountsVFS2(ctx context.Context, conf *config.
 			if err := c.k.VFS().SetMountReadOnly(mnt, false); err != nil {
 				return fmt.Errorf("failed to set mount at %q readwrite: %v", submount.Destination, err)
 			}
+			// Restore back to ReadOnly at the end.
 			defer func() {
 				if err := c.k.VFS().SetMountReadOnly(mnt, true); err != nil {
 					panic(fmt.Sprintf("failed to restore mount at %q back to readonly: %v", submount.Destination, err))