Added memfs support for nlink.

samples/memfs/fs.go

@@ -305,9 +305,10 @@ func (fs *memFS) MkDir(
 	// Set up attributes from the child, using the credentials of the calling
 	// process as owner (matching inode_init_owner, cf. http://goo.gl/5qavg8).
 	childAttrs := fuse.InodeAttributes{
-		Mode: req.Mode,
-		Uid:  req.Header.Uid,
-		Gid:  req.Header.Gid,
+		Nlink: 1,
+		Mode:  req.Mode,
+		Uid:   req.Header.Uid,
+		Gid:   req.Header.Gid,
 	}
 
 	// Allocate a child.
@@ -345,6 +346,7 @@ func (fs *memFS) CreateFile(
 	// process as owner (matching inode_init_owner, cf. http://goo.gl/5qavg8).
 	now := fs.clock.Now()
 	childAttrs := fuse.InodeAttributes{
+		Nlink:  1,
 		Mode:   req.Mode,
 		Atime:  now,
 		Mtime:  now,
@@ -408,7 +410,7 @@ func (fs *memFS) RmDir(
 	parent.RemoveChild(req.Name)
 
 	// Mark the child as unlinked.
-	child.linkCount--
+	child.attributes.Nlink--
 
 	return
 }
@@ -440,7 +442,7 @@ func (fs *memFS) Unlink(
 	parent.RemoveChild(req.Name)
 
 	// Mark the child as unlinked.
-	child.linkCount--
+	child.attributes.Nlink--
 
 	return
 }

samples/memfs/inode.go

@@ -47,13 +47,6 @@ type inode struct {
 
 	mu syncutil.InvariantMutex
 
-	// The number of times this inode is linked into a parent directory. This may
-	// be zero if the inode has been unlinked but not yet forgotten, because some
-	// process still has an  open file handle.
-	//
-	// INVARIANT: linkCount >= 0
-	linkCount int // GUARDED_BY(mu)
-
 	// The current attributes of this inode.
 	//
 	// INVARIANT: No non-permission mode bits are set besides os.ModeDir
@@ -87,7 +80,6 @@ type inode struct {
 
 // Create a new inode with the supplied attributes, which need not contain
 // time-related information (the inode object will take care of that).
-// Initially the link count is one.
 func newInode(
 	clock timeutil.Clock,
 	attrs fuse.InodeAttributes) (in *inode) {
@@ -99,7 +91,6 @@ func newInode(
 	// Create the object.
 	in = &inode{
 		clock:      clock,
-		linkCount:  1,
 		dir:        (attrs.Mode&os.ModeDir != 0),
 		attributes: attrs,
 	}
@@ -109,11 +100,6 @@ func newInode(
 }
 
 func (inode *inode) checkInvariants() {
-	// Check the link count.
-	if inode.linkCount < 0 {
-		panic(fmt.Sprintf("Negative link count: %v", inode.linkCount))
-	}
-
 	// No non-permission mode bits should be set besides os.ModeDir.
 	if inode.attributes.Mode & ^(os.ModePerm|os.ModeDir) != 0 {
 		panic(fmt.Sprintf("Unexpected mode: %v", inode.attributes.Mode))