Merge release-20200928.0-94-ge7bbe70f7 (automated)

4 files changed, 49 insertions, 59 deletions

diff --git a/pkg/sentry/fsimpl/devpts/devpts.go b/pkg/sentry/fsimpl/devpts/devpts.go
index 903135fae..8e34e26df 100644
--- a/pkg/sentry/fsimpl/devpts/devpts.go
+++ b/pkg/sentry/fsimpl/devpts/devpts.go
@@ -87,7 +87,9 @@ func (fstype FilesystemType) newFilesystem(vfsObj *vfs.VirtualFilesystem, creds
 	root.InodeAttrs.Init(creds, linux.UNNAMED_MAJOR, devMinor, 1, linux.ModeDirectory|0555)
 	root.OrderedChildren.Init(kernfs.OrderedChildrenOptions{})
 	root.EnableLeakCheck()
-	root.dentry.Init(root)
+
+	var rootD kernfs.Dentry
+	rootD.Init(&fs.Filesystem, root)
 
 	// Construct the pts master inode and dentry. Linux always uses inode
 	// id 2 for ptmx. See fs/devpts/inode.c:mknod_ptmx.
@@ -95,15 +97,14 @@ func (fstype FilesystemType) newFilesystem(vfsObj *vfs.VirtualFilesystem, creds
 		root: root,
 	}
 	master.InodeAttrs.Init(creds, linux.UNNAMED_MAJOR, devMinor, 2, linux.ModeCharacterDevice|0666)
-	master.dentry.Init(master)
 
 	// Add the master as a child of the root.
-	links := root.OrderedChildren.Populate(&root.dentry, map[string]*kernfs.Dentry{
-		"ptmx": &master.dentry,
+	links := root.OrderedChildren.Populate(map[string]kernfs.Inode{
+		"ptmx": master,
 	})
 	root.IncLinks(links)
 
-	return fs, &root.dentry, nil
+	return fs, &rootD, nil
 }
 
 // Release implements vfs.FilesystemImpl.Release.
@@ -117,24 +118,19 @@ func (fs *filesystem) Release(ctx context.Context) {
 // +stateify savable
 type rootInode struct {
 	implStatFS
-	kernfs.AlwaysValid
+	kernfs.InodeAlwaysValid
 	kernfs.InodeAttrs
 	kernfs.InodeDirectoryNoNewChildren
 	kernfs.InodeNotSymlink
+	kernfs.InodeTemporary // This holds no meaning as this inode can't be Looked up and is always valid.
 	kernfs.OrderedChildren
 	rootInodeRefs
 
 	locks vfs.FileLocks
 
-	// Keep a reference to this inode's dentry.
-	dentry kernfs.Dentry
-
 	// master is the master pty inode. Immutable.
 	master *masterInode
 
-	// root is the root directory inode for this filesystem. Immutable.
-	root *rootInode
-
 	// mu protects the fields below.
 	mu sync.Mutex `state:"nosave"`
 
@@ -173,21 +169,24 @@ func (i *rootInode) allocateTerminal(creds *auth.Credentials) (*Terminal, error)
 	// Linux always uses pty index + 3 as the inode id. See
 	// fs/devpts/inode.c:devpts_pty_new().
 	replica.InodeAttrs.Init(creds, i.InodeAttrs.DevMajor(), i.InodeAttrs.DevMinor(), uint64(idx+3), linux.ModeCharacterDevice|0600)
-	replica.dentry.Init(replica)
 	i.replicas[idx] = replica
 
 	return t, nil
 }
 
 // masterClose is called when the master end of t is closed.
-func (i *rootInode) masterClose(t *Terminal) {
+func (i *rootInode) masterClose(ctx context.Context, t *Terminal) {
 	i.mu.Lock()
 	defer i.mu.Unlock()
 
 	// Sanity check that replica with idx exists.
-	if _, ok := i.replicas[t.n]; !ok {
+	ri, ok := i.replicas[t.n]
+	if !ok {
 		panic(fmt.Sprintf("pty with index %d does not exist", t.n))
 	}
+
+	// Drop the ref on replica inode taken during rootInode.allocateTerminal.
+	ri.DecRef(ctx)
 	delete(i.replicas, t.n)
 }
 
@@ -203,16 +202,22 @@ func (i *rootInode) Open(ctx context.Context, rp *vfs.ResolvingPath, d *kernfs.D
 }
 
 // Lookup implements kernfs.Inode.Lookup.
-func (i *rootInode) Lookup(ctx context.Context, name string) (*kernfs.Dentry, error) {
+func (i *rootInode) Lookup(ctx context.Context, name string) (kernfs.Inode, error) {
+	// Check if a static entry was looked up.
+	if d, err := i.OrderedChildren.Lookup(ctx, name); err == nil {
+		return d, nil
+	}
+
+	// Not a static entry.
 	idx, err := strconv.ParseUint(name, 10, 32)
 	if err != nil {
 		return nil, syserror.ENOENT
 	}
 	i.mu.Lock()
 	defer i.mu.Unlock()
-	if si, ok := i.replicas[uint32(idx)]; ok {
-		si.dentry.IncRef()
-		return &si.dentry, nil
+	if ri, ok := i.replicas[uint32(idx)]; ok {
+		ri.IncRef() // This ref is passed to the dentry upon creation via Init.
+		return ri, nil
 
 	}
 	return nil, syserror.ENOENT
@@ -243,8 +248,8 @@ func (i *rootInode) IterDirents(ctx context.Context, cb vfs.IterDirentsCallback,
 }
 
 // DecRef implements kernfs.Inode.DecRef.
-func (i *rootInode) DecRef(context.Context) {
-	i.rootInodeRefs.DecRef(i.Destroy)
+func (i *rootInode) DecRef(ctx context.Context) {
+	i.rootInodeRefs.DecRef(func() { i.Destroy(ctx) })
 }
 
 // +stateify savable
diff --git a/pkg/sentry/fsimpl/devpts/devpts_state_autogen.go b/pkg/sentry/fsimpl/devpts/devpts_state_autogen.go
index d2c9ffa7d..12bb996cb 100644
--- a/pkg/sentry/fsimpl/devpts/devpts_state_autogen.go
+++ b/pkg/sentry/fsimpl/devpts/devpts_state_autogen.go
@@ -58,16 +58,15 @@ func (i *rootInode) StateTypeName() string {
 func (i *rootInode) StateFields() []string {
 	return []string{
 		"implStatFS",
-		"AlwaysValid",
+		"InodeAlwaysValid",
 		"InodeAttrs",
 		"InodeDirectoryNoNewChildren",
 		"InodeNotSymlink",
+		"InodeTemporary",
 		"OrderedChildren",
 		"rootInodeRefs",
 		"locks",
-		"dentry",
 		"master",
-		"root",
 		"replicas",
 		"nextIdx",
 	}
@@ -78,36 +77,34 @@ func (i *rootInode) beforeSave() {}
 func (i *rootInode) StateSave(stateSinkObject state.Sink) {
 	i.beforeSave()
 	stateSinkObject.Save(0, &i.implStatFS)
-	stateSinkObject.Save(1, &i.AlwaysValid)
+	stateSinkObject.Save(1, &i.InodeAlwaysValid)
 	stateSinkObject.Save(2, &i.InodeAttrs)
 	stateSinkObject.Save(3, &i.InodeDirectoryNoNewChildren)
 	stateSinkObject.Save(4, &i.InodeNotSymlink)
-	stateSinkObject.Save(5, &i.OrderedChildren)
-	stateSinkObject.Save(6, &i.rootInodeRefs)
-	stateSinkObject.Save(7, &i.locks)
-	stateSinkObject.Save(8, &i.dentry)
+	stateSinkObject.Save(5, &i.InodeTemporary)
+	stateSinkObject.Save(6, &i.OrderedChildren)
+	stateSinkObject.Save(7, &i.rootInodeRefs)
+	stateSinkObject.Save(8, &i.locks)
 	stateSinkObject.Save(9, &i.master)
-	stateSinkObject.Save(10, &i.root)
-	stateSinkObject.Save(11, &i.replicas)
-	stateSinkObject.Save(12, &i.nextIdx)
+	stateSinkObject.Save(10, &i.replicas)
+	stateSinkObject.Save(11, &i.nextIdx)
 }
 
 func (i *rootInode) afterLoad() {}
 
 func (i *rootInode) StateLoad(stateSourceObject state.Source) {
 	stateSourceObject.Load(0, &i.implStatFS)
-	stateSourceObject.Load(1, &i.AlwaysValid)
+	stateSourceObject.Load(1, &i.InodeAlwaysValid)
 	stateSourceObject.Load(2, &i.InodeAttrs)
 	stateSourceObject.Load(3, &i.InodeDirectoryNoNewChildren)
 	stateSourceObject.Load(4, &i.InodeNotSymlink)
-	stateSourceObject.Load(5, &i.OrderedChildren)
-	stateSourceObject.Load(6, &i.rootInodeRefs)
-	stateSourceObject.Load(7, &i.locks)
-	stateSourceObject.Load(8, &i.dentry)
+	stateSourceObject.Load(5, &i.InodeTemporary)
+	stateSourceObject.Load(6, &i.OrderedChildren)
+	stateSourceObject.Load(7, &i.rootInodeRefs)
+	stateSourceObject.Load(8, &i.locks)
 	stateSourceObject.Load(9, &i.master)
-	stateSourceObject.Load(10, &i.root)
-	stateSourceObject.Load(11, &i.replicas)
-	stateSourceObject.Load(12, &i.nextIdx)
+	stateSourceObject.Load(10, &i.replicas)
+	stateSourceObject.Load(11, &i.nextIdx)
 }
 
 func (i *implStatFS) StateTypeName() string {
@@ -220,7 +217,6 @@ func (mi *masterInode) StateFields() []string {
 		"InodeNotDirectory",
 		"InodeNotSymlink",
 		"locks",
-		"dentry",
 		"root",
 	}
 }
@@ -235,8 +231,7 @@ func (mi *masterInode) StateSave(stateSinkObject state.Sink) {
 	stateSinkObject.Save(3, &mi.InodeNotDirectory)
 	stateSinkObject.Save(4, &mi.InodeNotSymlink)
 	stateSinkObject.Save(5, &mi.locks)
-	stateSinkObject.Save(6, &mi.dentry)
-	stateSinkObject.Save(7, &mi.root)
+	stateSinkObject.Save(6, &mi.root)
 }
 
 func (mi *masterInode) afterLoad() {}
@@ -248,8 +243,7 @@ func (mi *masterInode) StateLoad(stateSourceObject state.Source) {
 	stateSourceObject.Load(3, &mi.InodeNotDirectory)
 	stateSourceObject.Load(4, &mi.InodeNotSymlink)
 	stateSourceObject.Load(5, &mi.locks)
-	stateSourceObject.Load(6, &mi.dentry)
-	stateSourceObject.Load(7, &mi.root)
+	stateSourceObject.Load(6, &mi.root)
 }
 
 func (mfd *masterFileDescription) StateTypeName() string {
@@ -334,7 +328,6 @@ func (ri *replicaInode) StateFields() []string {
 		"InodeNotDirectory",
 		"InodeNotSymlink",
 		"locks",
-		"dentry",
 		"root",
 		"t",
 	}
@@ -350,9 +343,8 @@ func (ri *replicaInode) StateSave(stateSinkObject state.Sink) {
 	stateSinkObject.Save(3, &ri.InodeNotDirectory)
 	stateSinkObject.Save(4, &ri.InodeNotSymlink)
 	stateSinkObject.Save(5, &ri.locks)
-	stateSinkObject.Save(6, &ri.dentry)
-	stateSinkObject.Save(7, &ri.root)
-	stateSinkObject.Save(8, &ri.t)
+	stateSinkObject.Save(6, &ri.root)
+	stateSinkObject.Save(7, &ri.t)
 }
 
 func (ri *replicaInode) afterLoad() {}
@@ -364,9 +356,8 @@ func (ri *replicaInode) StateLoad(stateSourceObject state.Source) {
 	stateSourceObject.Load(3, &ri.InodeNotDirectory)
 	stateSourceObject.Load(4, &ri.InodeNotSymlink)
 	stateSourceObject.Load(5, &ri.locks)
-	stateSourceObject.Load(6, &ri.dentry)
-	stateSourceObject.Load(7, &ri.root)
-	stateSourceObject.Load(8, &ri.t)
+	stateSourceObject.Load(6, &ri.root)
+	stateSourceObject.Load(7, &ri.t)
 }
 
 func (rfd *replicaFileDescription) StateTypeName() string {
diff --git a/pkg/sentry/fsimpl/devpts/master.go b/pkg/sentry/fsimpl/devpts/master.go
index 69c2fe951..fda30fb93 100644
--- a/pkg/sentry/fsimpl/devpts/master.go
+++ b/pkg/sentry/fsimpl/devpts/master.go
@@ -42,9 +42,6 @@ type masterInode struct {
 
 	locks vfs.FileLocks
 
-	// Keep a reference to this inode's dentry.
-	dentry kernfs.Dentry
-
 	// root is the devpts root inode.
 	root *rootInode
 }
@@ -103,7 +100,7 @@ var _ vfs.FileDescriptionImpl = (*masterFileDescription)(nil)
 
 // Release implements vfs.FileDescriptionImpl.Release.
 func (mfd *masterFileDescription) Release(ctx context.Context) {
-	mfd.inode.root.masterClose(mfd.t)
+	mfd.inode.root.masterClose(ctx, mfd.t)
 }
 
 // EventRegister implements waiter.Waitable.EventRegister.
diff --git a/pkg/sentry/fsimpl/devpts/replica.go b/pkg/sentry/fsimpl/devpts/replica.go
index 6515c5536..70c68cf0a 100644
--- a/pkg/sentry/fsimpl/devpts/replica.go
+++ b/pkg/sentry/fsimpl/devpts/replica.go
@@ -41,9 +41,6 @@ type replicaInode struct {
 
 	locks vfs.FileLocks
 
-	// Keep a reference to this inode's dentry.
-	dentry kernfs.Dentry
-
 	// root is the devpts root inode.
 	root *rootInode