From c38463a12226ba4906b311ab05f39f4b969b4347 Mon Sep 17 00:00:00 2001
From: Aaron Jacobs <jacobsa@google.com>
Date: Mon, 2 Mar 2015 14:40:28 +1100
Subject: [PATCH] Fixed broken invariants at construction.

---
 samples/memfs/dir.go |  6 ++++++
 samples/memfs/fs.go  | 17 ++++++++++++-----
 2 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/samples/memfs/dir.go b/samples/memfs/dir.go
index 7e59984..5272e67 100644
--- a/samples/memfs/dir.go
+++ b/samples/memfs/dir.go
@@ -31,5 +31,11 @@ type memDir struct {
 	//
 	// TODO(jacobsa): Add good tests exercising concurrent modifications while
 	// doing readdir, seekdir, etc. calls.
+	//
+	// INVIARANT: For each i < len(entries)-1, entries[i].Offset = i+1
 	entries []fuseutil.Dirent
 }
+
+func newDir() *memDir
+
+func (d *memDir) checkInvariants()
diff --git a/samples/memfs/fs.go b/samples/memfs/fs.go
index 9193964..ce8ea18 100644
--- a/samples/memfs/fs.go
+++ b/samples/memfs/fs.go
@@ -47,13 +47,20 @@ type memFS struct {
 
 // Create a file system that stores data and metadata in memory.
 func NewMemFS(
-	clock timeutil.Clock) (fs fuse.FileSystem) {
-	fs = &memFS{
-		clock: clock,
+	clock timeutil.Clock) fuse.FileSystem {
+	// Set up the basic struct.
+	fs := &memFS{
+		clock:  clock,
+		inodes: make([]inode, fuse.RootInodeID+1),
 	}
 
-	fs.(*memFS).mu = syncutil.NewInvariantMutex(fs.(*memFS).checkInvariants)
-	return
+	// Set up the root inode.
+	fs.inodes[fuse.RootInodeID].impl = newDir()
+
+	// Set up invariant checking.
+	fs.mu = syncutil.NewInvariantMutex(fs.checkInvariants)
+
+	return fs
 }
 
 func (fs *memFS) checkInvariants() {