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-rw-r--r--pkg/sentry/fs/mock.go1
-rw-r--r--pkg/sentry/fs/mount.go73
-rw-r--r--pkg/sentry/fs/mount_test.go167
-rw-r--r--pkg/sentry/fs/mounts.go258
-rw-r--r--pkg/sentry/fs/proc/mounts.go48
-rw-r--r--runsc/boot/fs.go16
6 files changed, 317 insertions, 246 deletions
diff --git a/pkg/sentry/fs/mock.go b/pkg/sentry/fs/mock.go
index 064943c5b..ff04e9b22 100644
--- a/pkg/sentry/fs/mock.go
+++ b/pkg/sentry/fs/mock.go
@@ -62,7 +62,6 @@ func NewMockMountSource(cache *DirentCache) *MountSource {
return &MountSource{
MountSourceOperations: &MockMountSourceOps{keep: keep},
fscache: cache,
- children: make(map[*MountSource]struct{}),
}
}
diff --git a/pkg/sentry/fs/mount.go b/pkg/sentry/fs/mount.go
index 63fcf4380..41e0d285b 100644
--- a/pkg/sentry/fs/mount.go
+++ b/pkg/sentry/fs/mount.go
@@ -17,7 +17,6 @@ package fs
import (
"bytes"
"fmt"
- "sync"
"sync/atomic"
"gvisor.googlesource.com/gvisor/pkg/refs"
@@ -89,15 +88,7 @@ func (i InodeMappings) String() string {
// one mount source. Each file object may only be represented using one inode
// object in a sentry instance.
//
-// This is an amalgamation of structs super_block, vfsmount, and mount, while
-// MountSourceOperations is akin to struct super_operations.
-//
-// Hence, mount source also contains common mounted file system state, such as
-// mount flags, the root Dirent, and children mounts. For now, this
-// amalgamation implies that a mount source cannot be shared by multiple mounts
-// (e.g. cannot be mounted at different locations).
-//
-// TODO(b/63601033): Move mount-specific information out of MountSource.
+// TODO(b/63601033): Move Flags out of MountSource to Mount.
//
// +stateify savable
type MountSource struct {
@@ -128,22 +119,6 @@ type MountSource struct {
//
// direntRefs must be atomically changed.
direntRefs uint64
-
- // mu protects the fields below, which are set by the MountNamespace
- // during MountSource/Unmount.
- mu sync.Mutex `state:"nosave"`
-
- // id is a unique id for this mount.
- id uint64
-
- // root is the root Dirent of this mount.
- root *Dirent
-
- // parent is the parent MountSource, or nil if this MountSource is the root.
- parent *MountSource
-
- // children are the child MountSources of this MountSource.
- children map[*MountSource]struct{}
}
// DefaultDirentCacheSize is the number of Dirents that the VFS can hold an
@@ -162,53 +137,7 @@ func NewMountSource(mops MountSourceOperations, filesystem Filesystem, flags Mou
Flags: flags,
FilesystemType: fsType,
fscache: NewDirentCache(DefaultDirentCacheSize),
- children: make(map[*MountSource]struct{}),
- }
-}
-
-// Parent returns the parent mount, or nil if this mount is the root.
-func (msrc *MountSource) Parent() *MountSource {
- msrc.mu.Lock()
- defer msrc.mu.Unlock()
- return msrc.parent
-}
-
-// ID returns the ID of this mount.
-func (msrc *MountSource) ID() uint64 {
- msrc.mu.Lock()
- defer msrc.mu.Unlock()
- return msrc.id
-}
-
-// Children returns the (immediate) children of this MountSource.
-func (msrc *MountSource) Children() []*MountSource {
- msrc.mu.Lock()
- defer msrc.mu.Unlock()
-
- ms := make([]*MountSource, 0, len(msrc.children))
- for c := range msrc.children {
- ms = append(ms, c)
}
- return ms
-}
-
-// Submounts returns all mounts that are descendants of this mount.
-func (msrc *MountSource) Submounts() []*MountSource {
- var ms []*MountSource
- for _, c := range msrc.Children() {
- ms = append(ms, c)
- ms = append(ms, c.Submounts()...)
- }
- return ms
-}
-
-// Root returns the root dirent of this mount. Callers must call DecRef on the
-// returned dirent.
-func (msrc *MountSource) Root() *Dirent {
- msrc.mu.Lock()
- defer msrc.mu.Unlock()
- msrc.root.IncRef()
- return msrc.root
}
// DirentRefs returns the current mount direntRefs.
diff --git a/pkg/sentry/fs/mount_test.go b/pkg/sentry/fs/mount_test.go
index 9f7fbeff2..2e2716643 100644
--- a/pkg/sentry/fs/mount_test.go
+++ b/pkg/sentry/fs/mount_test.go
@@ -32,6 +32,27 @@ func cacheReallyContains(cache *DirentCache, d *Dirent) bool {
return false
}
+func mountPathsAre(root *Dirent, got []*Mount, want ...string) error {
+ gotPaths := make(map[string]struct{}, len(got))
+ gotStr := make([]string, len(got))
+ for i, g := range got {
+ groot := g.Root()
+ name, _ := groot.FullName(root)
+ groot.DecRef()
+ gotStr[i] = name
+ gotPaths[name] = struct{}{}
+ }
+ if len(got) != len(want) {
+ return fmt.Errorf("mount paths are different, got: %q, want: %q", gotStr, want)
+ }
+ for _, w := range want {
+ if _, ok := gotPaths[w]; !ok {
+ return fmt.Errorf("no mount with path %q found", w)
+ }
+ }
+ return nil
+}
+
// TestMountSourceOnlyCachedOnce tests that a Dirent that is mounted over only ends
// up in a single Dirent Cache. NOTE(b/63848693): Having a dirent in multiple
// caches causes major consistency issues.
@@ -91,8 +112,7 @@ func TestMountSourceOnlyCachedOnce(t *testing.T) {
}
}
-// Test that mounts have proper parent/child relationships.
-func TestMountSourceParentChildRelationship(t *testing.T) {
+func TestAllMountsUnder(t *testing.T) {
ctx := contexttest.Context(t)
rootCache := NewDirentCache(100)
@@ -122,101 +142,130 @@ func TestMountSourceParentChildRelationship(t *testing.T) {
if err != nil {
t.Fatalf("could not find path %q in mount manager: %v", p, err)
}
+
submountInode := NewMockInode(ctx, NewMockMountSource(nil), StableAttr{
Type: Directory,
})
if err := mm.Mount(ctx, d, submountInode); err != nil {
t.Fatalf("could not mount at %q: %v", p, err)
}
+ d.DecRef()
}
- // mm root should contain all submounts (and does not include the root
- // mount).
- allMountSources := rootDirent.Inode.MountSource.Submounts()
- if err := mountPathsAre(rootDirent, allMountSources, paths...); err != nil {
+ // mm root should contain all submounts (and does not include the root mount).
+ rootMnt := mm.FindMount(rootDirent)
+ submounts := mm.AllMountsUnder(rootMnt)
+ allPaths := append(paths, "/")
+ if err := mountPathsAre(rootDirent, submounts, allPaths...); err != nil {
t.Error(err)
}
// Each mount should have a unique ID.
foundIDs := make(map[uint64]struct{})
- for _, m := range allMountSources {
- id := m.ID()
- if _, ok := foundIDs[id]; ok {
- t.Errorf("got multiple mounts with id %d", id)
+ for _, m := range submounts {
+ if _, ok := foundIDs[m.ID]; ok {
+ t.Errorf("got multiple mounts with id %d", m.ID)
}
- foundIDs[id] = struct{}{}
+ foundIDs[m.ID] = struct{}{}
}
// Root mount should have no parent.
- rootMountSource := mm.root.Inode.MountSource
- if p := rootMountSource.Parent(); p != nil {
+ if p := rootMnt.ParentID; p != invalidMountID {
t.Errorf("root.Parent got %v wanted nil", p)
}
- // Root mount should have 2 children: foo and waldo.
- rootChildren := rootMountSource.Children()
- if err := mountPathsAre(rootDirent, rootChildren, "/foo", "/waldo"); err != nil {
- t.Error(err)
- }
- // All root mount children should have root as parent.
- for _, c := range rootChildren {
- if p := c.Parent(); p != rootMountSource {
- t.Errorf("root mount child got parent %+v, wanted root mount", p)
- }
- }
-
- // "foo" mount should have two children: /foo/bar, and /foo/qux.
+ // Check that "foo" mount has 3 children.
maxTraversals = 0
d, err := mm.FindLink(ctx, rootDirent, nil, "/foo", &maxTraversals)
if err != nil {
t.Fatalf("could not find path %q in mount manager: %v", "/foo", err)
}
- fooMountSource := d.Inode.MountSource
- fooMountSourceChildren := fooMountSource.Children()
- if err := mountPathsAre(rootDirent, fooMountSourceChildren, "/foo/bar", "/foo/qux"); err != nil {
- t.Error(err)
- }
- // Each child should have fooMountSource as parent.
- for _, c := range fooMountSourceChildren {
- if p := c.Parent(); p != fooMountSource {
- t.Errorf("foo mount child got parent %+v, wanted foo mount", p)
- }
- }
- // Submounts of foo are /foo/bar, /foo/qux, and /foo/bar/baz.
- if err := mountPathsAre(rootDirent, fooMountSource.Submounts(), "/foo/bar", "/foo/qux", "/foo/bar/baz"); err != nil {
+ defer d.DecRef()
+ submounts = mm.AllMountsUnder(mm.FindMount(d))
+ if err := mountPathsAre(rootDirent, submounts, "/foo", "/foo/bar", "/foo/qux", "/foo/bar/baz"); err != nil {
t.Error(err)
}
- // "waldo" mount should have no submounts or children.
+ // "waldo" mount should have no children.
maxTraversals = 0
waldo, err := mm.FindLink(ctx, rootDirent, nil, "/waldo", &maxTraversals)
if err != nil {
t.Fatalf("could not find path %q in mount manager: %v", "/waldo", err)
}
- waldoMountSource := waldo.Inode.MountSource
- if got := len(waldoMountSource.Children()); got != 0 {
- t.Errorf("waldo got %d children, wanted 0", got)
- }
- if got := len(waldoMountSource.Submounts()); got != 0 {
- t.Errorf("waldo got %d children, wanted 0", got)
+ defer waldo.DecRef()
+ submounts = mm.AllMountsUnder(mm.FindMount(waldo))
+ if err := mountPathsAre(rootDirent, submounts, "/waldo"); err != nil {
+ t.Error(err)
}
}
-func mountPathsAre(root *Dirent, got []*MountSource, want ...string) error {
- if len(got) != len(want) {
- return fmt.Errorf("mount paths have different lengths: got %d want %d", len(got), len(want))
+func TestUnmount(t *testing.T) {
+ ctx := contexttest.Context(t)
+
+ rootCache := NewDirentCache(100)
+ rootInode := NewMockInode(ctx, NewMockMountSource(rootCache), StableAttr{
+ Type: Directory,
+ })
+ mm, err := NewMountNamespace(ctx, rootInode)
+ if err != nil {
+ t.Fatalf("NewMountNamespace failed: %v", err)
}
- gotPaths := make(map[string]struct{}, len(got))
- for _, g := range got {
- groot := g.Root()
- n, _ := groot.FullName(root)
- groot.DecRef()
- gotPaths[n] = struct{}{}
+ rootDirent := mm.Root()
+ defer rootDirent.DecRef()
+
+ // Add mounts at the following paths:
+ paths := []string{
+ "/foo",
+ "/foo/bar",
+ "/foo/bar/goo",
+ "/foo/bar/goo/abc",
+ "/foo/abc",
+ "/foo/def",
+ "/waldo",
+ "/wally",
}
- for _, w := range want {
- if _, ok := gotPaths[w]; !ok {
- return fmt.Errorf("no mount with path %q found", w)
+
+ var maxTraversals uint
+ for _, p := range paths {
+ maxTraversals = 0
+ d, err := mm.FindLink(ctx, rootDirent, nil, p, &maxTraversals)
+ if err != nil {
+ t.Fatalf("could not find path %q in mount manager: %v", p, err)
+ }
+
+ submountInode := NewMockInode(ctx, NewMockMountSource(nil), StableAttr{
+ Type: Directory,
+ })
+ if err := mm.Mount(ctx, d, submountInode); err != nil {
+ t.Fatalf("could not mount at %q: %v", p, err)
+ }
+ d.DecRef()
+ }
+
+ allPaths := make([]string, len(paths)+1)
+ allPaths[0] = "/"
+ copy(allPaths[1:], paths)
+
+ rootMnt := mm.FindMount(rootDirent)
+ for i := len(paths) - 1; i >= 0; i-- {
+ maxTraversals = 0
+ p := paths[i]
+ d, err := mm.FindLink(ctx, rootDirent, nil, p, &maxTraversals)
+ if err != nil {
+ t.Fatalf("could not find path %q in mount manager: %v", p, err)
+ }
+
+ if err := mm.Unmount(ctx, d, false); err != nil {
+ t.Fatalf("could not unmount at %q: %v", p, err)
+ }
+ d.DecRef()
+
+ // Remove the path that has been unmounted and the check that the remaining
+ // mounts are still there.
+ allPaths = allPaths[:len(allPaths)-1]
+ submounts := mm.AllMountsUnder(rootMnt)
+ if err := mountPathsAre(rootDirent, submounts, allPaths...); err != nil {
+ t.Error(err)
}
}
- return nil
}
diff --git a/pkg/sentry/fs/mounts.go b/pkg/sentry/fs/mounts.go
index 01eb4607e..a5c52d7ba 100644
--- a/pkg/sentry/fs/mounts.go
+++ b/pkg/sentry/fs/mounts.go
@@ -16,6 +16,7 @@ package fs
import (
"fmt"
+ "math"
"path"
"strings"
"sync"
@@ -35,6 +36,94 @@ import (
// sane.
const DefaultTraversalLimit = 10
+const invalidMountID = math.MaxUint64
+
+// Mount represents a mount in the file system. It holds the root dirent for the
+// mount. It also points back to the dirent or mount where it was mounted over,
+// so that it can be restored when unmounted. The chained mount can be either:
+// - Mount: when it's mounted on top of another mount point.
+// - Dirent: when it's mounted on top of a dirent. In this case the mount is
+// called an "undo" mount and only 'root' is set. All other fields are
+// either invalid or nil.
+//
+// +stateify savable
+type Mount struct {
+ // ID is a unique id for this mount. It may be invalidMountID if this is
+ // used to cache a dirent that was mounted over.
+ ID uint64
+
+ // ParentID is the parent's mount unique id. It may be invalidMountID if this
+ // is the root mount or if this is used to cache a dirent that was mounted
+ // over.
+ ParentID uint64
+
+ // root is the root Dirent of this mount. A reference on this Dirent must be
+ // held through the lifetime of the Mount which contains it.
+ root *Dirent
+
+ // previous is the existing dirent or mount that this object was mounted over.
+ // It's nil for the root mount and for the last entry in the chain (always an
+ // "undo" mount).
+ previous *Mount
+}
+
+// newMount creates a new mount, taking a reference on 'root'. Caller must
+// release the reference when it's done with the mount.
+func newMount(id, pid uint64, root *Dirent) *Mount {
+ root.IncRef()
+ return &Mount{
+ ID: id,
+ ParentID: pid,
+ root: root,
+ }
+}
+
+// newRootMount creates a new root mount (no parent), taking a reference on
+// 'root'. Caller must release the reference when it's done with the mount.
+func newRootMount(id uint64, root *Dirent) *Mount {
+ root.IncRef()
+ return &Mount{
+ ID: id,
+ ParentID: invalidMountID,
+ root: root,
+ }
+}
+
+// newUndoMount creates a new undo mount, taking a reference on 'd'. Caller must
+// release the reference when it's done with the mount.
+func newUndoMount(d *Dirent) *Mount {
+ d.IncRef()
+ return &Mount{
+ ID: invalidMountID,
+ ParentID: invalidMountID,
+ root: d,
+ }
+}
+
+// Root returns the root dirent of this mount. Callers must call DecRef on the
+// returned dirent.
+func (m *Mount) Root() *Dirent {
+ m.root.IncRef()
+ return m.root
+}
+
+// IsRoot returns true if the mount has no parent.
+func (m *Mount) IsRoot() bool {
+ return !m.IsUndo() && m.ParentID == invalidMountID
+}
+
+// IsUndo returns true if 'm' is an undo mount that should be used to restore
+// the original dirent during unmount only and it's not a valid mount.
+func (m *Mount) IsUndo() bool {
+ if m.ID == invalidMountID {
+ if m.ParentID != invalidMountID {
+ panic(fmt.Sprintf("Undo mount with valid parentID: %+v", m))
+ }
+ return true
+ }
+ return false
+}
+
// MountNamespace defines a collection of mounts.
//
// +stateify savable
@@ -55,13 +144,16 @@ type MountNamespace struct {
// mu protects mounts and mountID counter.
mu sync.Mutex `state:"nosave"`
- // mounts is a map of the last mounted Dirent -> stack of old Dirents
- // that were mounted over, with the oldest mounted Dirent first and
- // more recent mounted Dirents at the end of the slice.
- //
- // A reference to all Dirents in mounts (keys and values) must be held
- // to ensure the Dirents are recoverable when unmounting.
- mounts map[*Dirent][]*Dirent
+ // mounts is a map of mounted Dirent -> Mount object. There are three
+ // possible cases:
+ // - Dirent is mounted over a mount point: the stored Mount object will be
+ // the Mount for that mount point.
+ // - Dirent is mounted over a regular (non-mount point) Dirent: the stored
+ // Mount object will be an "undo" mount containing the mounted-over
+ // Dirent.
+ // - Dirent is the root mount: the stored Mount object will be a root mount
+ // containing the Dirent itself.
+ mounts map[*Dirent]*Mount
// mountID is the next mount id to assign.
mountID uint64
@@ -72,18 +164,18 @@ type MountNamespace struct {
func NewMountNamespace(ctx context.Context, root *Inode) (*MountNamespace, error) {
creds := auth.CredentialsFromContext(ctx)
- root.MountSource.mu.Lock()
- defer root.MountSource.mu.Unlock()
-
- // Set the root dirent and id on the root mount.
+ // Set the root dirent and id on the root mount. The reference returned from
+ // NewDirent will be donated to the MountNamespace constructed below.
d := NewDirent(root, "/")
- root.MountSource.root = d
- root.MountSource.id = 1
+
+ mnts := map[*Dirent]*Mount{
+ d: newRootMount(1, d),
+ }
return &MountNamespace{
userns: creds.UserNamespace,
root: d,
- mounts: make(map[*Dirent][]*Dirent),
+ mounts: mnts,
mountID: 2,
}, nil
}
@@ -110,10 +202,9 @@ func (mns *MountNamespace) FlushMountSourceRefs() {
func (mns *MountNamespace) flushMountSourceRefsLocked() {
// Flush mounts' MountSource references.
- for current, stack := range mns.mounts {
- current.Inode.MountSource.FlushDirentRefs()
- for _, prev := range stack {
- prev.Inode.MountSource.FlushDirentRefs()
+ for _, mp := range mns.mounts {
+ for ; mp != nil; mp = mp.previous {
+ mp.root.Inode.MountSource.FlushDirentRefs()
}
}
@@ -136,12 +227,11 @@ func (mns *MountNamespace) destroy() {
mns.flushMountSourceRefsLocked()
// Teardown mounts.
- for current, mp := range mns.mounts {
+ for _, mp := range mns.mounts {
// Drop the mount reference on all mounted dirents.
- for _, d := range mp {
- d.DecRef()
+ for ; mp != nil; mp = mp.previous {
+ mp.root.DecRef()
}
- current.DecRef()
}
mns.mounts = nil
@@ -208,46 +298,34 @@ func (mns *MountNamespace) withMountLocked(node *Dirent, fn func() error) error
}
// Mount mounts a `inode` over the subtree at `node`.
-func (mns *MountNamespace) Mount(ctx context.Context, node *Dirent, inode *Inode) error {
- return mns.withMountLocked(node, func() error {
- // replacement already has one reference taken; this is the mount
- // reference.
- replacement, err := node.mount(ctx, inode)
+func (mns *MountNamespace) Mount(ctx context.Context, mountPoint *Dirent, inode *Inode) error {
+ return mns.withMountLocked(mountPoint, func() error {
+ replacement, err := mountPoint.mount(ctx, inode)
if err != nil {
return err
}
-
- // Set child/parent dirent relationship.
- parentMountSource := node.Inode.MountSource
- childMountSource := inode.MountSource
- parentMountSource.mu.Lock()
- defer parentMountSource.mu.Unlock()
- childMountSource.mu.Lock()
- defer childMountSource.mu.Unlock()
-
- parentMountSource.children[childMountSource] = struct{}{}
- childMountSource.parent = parentMountSource
+ defer replacement.DecRef()
// Set the mount's root dirent and id.
- childMountSource.root = replacement
- childMountSource.id = mns.mountID
+ parentMnt := mns.findMountLocked(mountPoint)
+ childMnt := newMount(mns.mountID, parentMnt.ID, replacement)
mns.mountID++
- // Drop node from its dirent cache.
- node.dropExtendedReference()
+ // Drop mountPoint from its dirent cache.
+ mountPoint.dropExtendedReference()
- // If node is already a mount point, push node on the stack so it can
+ // If mountPoint is already a mount, push mountPoint on the stack so it can
// be recovered on unmount.
- if stack, ok := mns.mounts[node]; ok {
- mns.mounts[replacement] = append(stack, node)
- delete(mns.mounts, node)
+ if prev := mns.mounts[mountPoint]; prev != nil {
+ childMnt.previous = prev
+ mns.mounts[replacement] = childMnt
+ delete(mns.mounts, mountPoint)
return nil
}
// Was not already mounted, just add another mount point.
- // Take a reference on node so it can be recovered on unmount.
- node.IncRef()
- mns.mounts[replacement] = []*Dirent{node}
+ childMnt.previous = newUndoMount(mountPoint)
+ mns.mounts[replacement] = childMnt
return nil
})
}
@@ -268,13 +346,13 @@ func (mns *MountNamespace) Unmount(ctx context.Context, node *Dirent, detachOnly
// This takes locks to prevent further walks to Dirents in this mount
// under the assumption that `node` is the root of the mount.
return mns.withMountLocked(node, func() error {
- origs, ok := mns.mounts[node]
+ orig, ok := mns.mounts[node]
if !ok {
// node is not a mount point.
return syserror.EINVAL
}
- if len(origs) == 0 {
+ if orig.previous == nil {
panic("cannot unmount initial dirent")
}
@@ -298,44 +376,62 @@ func (mns *MountNamespace) Unmount(ctx context.Context, node *Dirent, detachOnly
}
}
- // Lock the parent MountSource first, if it exists. We are
- // holding mns.Lock, so the parent can not change out
- // from under us.
- parent := m.Parent()
- if parent != nil {
- parent.mu.Lock()
- defer parent.mu.Unlock()
+ prev := orig.previous
+ if err := node.unmount(ctx, prev.root); err != nil {
+ return err
}
- // Lock the mount that is being unmounted.
- m.mu.Lock()
- defer m.mu.Unlock()
-
- if m.parent != nil {
- // Sanity check.
- if _, ok := m.parent.children[m]; !ok {
- panic(fmt.Sprintf("mount %+v is not a child of parent %+v", m, m.parent))
+ if prev.previous == nil {
+ if !prev.IsUndo() {
+ panic(fmt.Sprintf("Last mount in the chain must be a undo mount: %+v", prev))
}
- delete(m.parent.children, m)
+ // Drop mount reference taken at the end of MountNamespace.Mount.
+ prev.root.DecRef()
+ } else {
+ mns.mounts[prev.root] = prev
}
+ delete(mns.mounts, node)
- original := origs[len(origs)-1]
- if err := node.unmount(ctx, original); err != nil {
- return err
- }
+ return nil
+ })
+}
+
+// FindMount returns the mount that 'd' belongs to. It walks the dirent back
+// until a mount is found. It may return nil if no mount was found.
+func (mns *MountNamespace) FindMount(d *Dirent) *Mount {
+ mns.mu.Lock()
+ defer mns.mu.Unlock()
+ renameMu.Lock()
+ defer renameMu.Unlock()
- switch {
- case len(origs) > 1:
- mns.mounts[original] = origs[:len(origs)-1]
- case len(origs) == 1:
- // Drop mount reference taken at the end of
- // MountNamespace.Mount.
- original.DecRef()
+ return mns.findMountLocked(d)
+}
+
+func (mns *MountNamespace) findMountLocked(d *Dirent) *Mount {
+ for {
+ if mnt := mns.mounts[d]; mnt != nil {
+ return mnt
+ }
+ if d.parent == nil {
+ return nil
}
+ d = d.parent
+ }
+}
- delete(mns.mounts, node)
- return nil
- })
+// AllMountsUnder returns a slice of all mounts under the parent, including
+// itself.
+func (mns *MountNamespace) AllMountsUnder(parent *Mount) []*Mount {
+ mns.mu.Lock()
+ defer mns.mu.Unlock()
+
+ var rv []*Mount
+ for _, mp := range mns.mounts {
+ if !mp.IsUndo() && mp.root.descendantOf(parent.root) {
+ rv = append(rv, mp)
+ }
+ }
+ return rv
}
// FindLink returns an Dirent from a given node, which may be a symlink.
diff --git a/pkg/sentry/fs/proc/mounts.go b/pkg/sentry/fs/proc/mounts.go
index b5e01301f..1f7817947 100644
--- a/pkg/sentry/fs/proc/mounts.go
+++ b/pkg/sentry/fs/proc/mounts.go
@@ -27,7 +27,7 @@ import (
// forEachMountSource runs f for the process root mount and each mount that is a
// descendant of the root.
-func forEachMountSource(t *kernel.Task, fn func(string, *fs.MountSource)) {
+func forEachMount(t *kernel.Task, fn func(string, *fs.Mount)) {
var fsctx *kernel.FSContext
t.WithMuLocked(func(t *kernel.Task) {
fsctx = t.FSContext()
@@ -46,16 +46,14 @@ func forEachMountSource(t *kernel.Task, fn func(string, *fs.MountSource)) {
}
defer rootDir.DecRef()
- if rootDir.Inode == nil {
- panic(fmt.Sprintf("root dirent has nil inode: %+v", rootDir))
- }
- if rootDir.Inode.MountSource == nil {
- panic(fmt.Sprintf("root dirent has nil mount: %+v", rootDir))
+ mnt := t.MountNamespace().FindMount(rootDir)
+ if mnt == nil {
+ // Has it just been unmounted?
+ return
}
-
- ms := append(rootDir.Inode.MountSource.Submounts(), rootDir.Inode.MountSource)
+ ms := t.MountNamespace().AllMountsUnder(mnt)
sort.Slice(ms, func(i, j int) bool {
- return ms[i].ID() < ms[j].ID()
+ return ms[i].ID < ms[j].ID
})
for _, m := range ms {
mroot := m.Root()
@@ -89,26 +87,27 @@ func (mif *mountInfoFile) ReadSeqFileData(ctx context.Context, handle seqfile.Se
}
var buf bytes.Buffer
- forEachMountSource(mif.t, func(mountPath string, m *fs.MountSource) {
+ forEachMount(mif.t, func(mountPath string, m *fs.Mount) {
// Format:
// 36 35 98:0 /mnt1 /mnt2 rw,noatime master:1 - ext3 /dev/root rw,errors=continue
// (1)(2)(3) (4) (5) (6) (7) (8) (9) (10) (11)
// (1) MountSource ID.
- fmt.Fprintf(&buf, "%d ", m.ID())
+ fmt.Fprintf(&buf, "%d ", m.ID)
// (2) Parent ID (or this ID if there is no parent).
- pID := m.ID()
- if p := m.Parent(); p != nil {
- pID = p.ID()
+ pID := m.ID
+ if !m.IsRoot() && !m.IsUndo() {
+ pID = m.ParentID
}
fmt.Fprintf(&buf, "%d ", pID)
// (3) Major:Minor device ID. We don't have a superblock, so we
// just use the root inode device number.
mroot := m.Root()
+ defer mroot.DecRef()
+
sa := mroot.Inode.StableAttr
- mroot.DecRef()
fmt.Fprintf(&buf, "%d:%d ", sa.DeviceFileMajor, sa.DeviceFileMinor)
// (4) Root: the pathname of the directory in the filesystem
@@ -122,14 +121,15 @@ func (mif *mountInfoFile) ReadSeqFileData(ctx context.Context, handle seqfile.Se
fmt.Fprintf(&buf, "%s ", mountPath)
// (6) Mount options.
+ flags := mroot.Inode.MountSource.Flags
opts := "rw"
- if m.Flags.ReadOnly {
+ if flags.ReadOnly {
opts = "ro"
}
- if m.Flags.NoAtime {
+ if flags.NoAtime {
opts += ",noatime"
}
- if m.Flags.NoExec {
+ if flags.NoExec {
opts += ",noexec"
}
fmt.Fprintf(&buf, "%s ", opts)
@@ -139,7 +139,7 @@ func (mif *mountInfoFile) ReadSeqFileData(ctx context.Context, handle seqfile.Se
fmt.Fprintf(&buf, "- ")
// (9) Filesystem type.
- fmt.Fprintf(&buf, "%s ", m.FilesystemType)
+ fmt.Fprintf(&buf, "%s ", mroot.Inode.MountSource.FilesystemType)
// (10) Mount source: filesystem-specific information or "none".
fmt.Fprintf(&buf, "none ")
@@ -171,7 +171,7 @@ func (mf *mountsFile) ReadSeqFileData(ctx context.Context, handle seqfile.SeqHan
}
var buf bytes.Buffer
- forEachMountSource(mf.t, func(mountPath string, m *fs.MountSource) {
+ forEachMount(mf.t, func(mountPath string, m *fs.Mount) {
// Format:
// <special device or remote filesystem> <mount point> <filesystem type> <mount options> <needs dump> <fsck order>
//
@@ -182,11 +182,15 @@ func (mf *mountsFile) ReadSeqFileData(ctx context.Context, handle seqfile.SeqHan
// Only ro/rw option is supported for now.
//
// The "needs dump"and fsck flags are always 0, which is allowed.
+ root := m.Root()
+ defer root.DecRef()
+
+ flags := root.Inode.MountSource.Flags
opts := "rw"
- if m.Flags.ReadOnly {
+ if flags.ReadOnly {
opts = "ro"
}
- fmt.Fprintf(&buf, "%s %s %s %s %d %d\n", "none", mountPath, m.FilesystemType, opts, 0, 0)
+ fmt.Fprintf(&buf, "%s %s %s %s %d %d\n", "none", mountPath, root.Inode.MountSource.FilesystemType, opts, 0, 0)
})
return []seqfile.SeqData{{Buf: buf.Bytes(), Handle: (*mountsFile)(nil)}}, 0
diff --git a/runsc/boot/fs.go b/runsc/boot/fs.go
index 1611dda2c..bc05b3491 100644
--- a/runsc/boot/fs.go
+++ b/runsc/boot/fs.go
@@ -685,27 +685,21 @@ func destroyContainerFS(ctx context.Context, cid string, k *kernel.Kernel) error
// Iterate through all submounts and unmount them. We unmount lazily by
// setting detach=true, so we can unmount in any order.
- for _, m := range containerRootDirent.Inode.MountSource.Submounts() {
+ mnt := mns.FindMount(containerRootDirent)
+ for _, m := range mns.AllMountsUnder(mnt) {
root := m.Root()
defer root.DecRef()
// Do a best-effort unmount by flushing the refs and unmount
// with "detach only = true". Unmount returns EINVAL when the mount point
// doesn't exist, i.e. it has already been unmounted.
- log.Debugf("Unmounting container submount %q", root.BaseName())
- m.FlushDirentRefs()
+ log.Debugf("Unmounting container mount %q", root.BaseName())
+ root.Inode.MountSource.FlushDirentRefs()
if err := mns.Unmount(ctx, root, true /* detach only */); err != nil && err != syserror.EINVAL {
- return fmt.Errorf("unmounting container submount %q: %v", root.BaseName(), err)
+ return fmt.Errorf("unmounting container mount %q: %v", root.BaseName(), err)
}
}
- // Unmount the container root itself.
- log.Debugf("Unmounting container root %q", containerRoot)
- containerRootDirent.Inode.MountSource.FlushDirentRefs()
- if err := mns.Unmount(ctx, containerRootDirent, true /* detach only */); err != nil {
- return fmt.Errorf("unmounting container root mount %q: %v", containerRootDirent.BaseName(), err)
- }
-
// Get a reference to the parent directory and remove the root
// container directory.
maxTraversals = 0
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-06 01:43:21 +0000