From a787be87bb543f377e3398307062ac6ad044830f Mon Sep 17 00:00:00 2001
From: Aaron Jacobs <jacobsa@google.com>
Date: Mon, 30 Mar 2015 16:28:02 +1100
Subject: [PATCH] fsImpl.checkInvariants

---
 samples/forgetfs/forget_fs.go | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/samples/forgetfs/forget_fs.go b/samples/forgetfs/forget_fs.go
index 6af2ccc..582a115 100644
--- a/samples/forgetfs/forget_fs.go
+++ b/samples/forgetfs/forget_fs.go
@@ -97,7 +97,7 @@ type fsImpl struct {
 
 	// An index of inode by ID, for all IDs we have issued.
 	//
-	// INVARIANT: For each v, v.lookupCount >= 0
+	// INVARIANT: For each v in inodes, v.lookupCount >= 0
 	//
 	// GUARDED_BY(mu)
 	inodes map[fuseops.InodeID]*inode
@@ -116,7 +116,21 @@ type inode struct {
 }
 
 // LOCKS_REQUIRED(fs.mu)
-func (fs *fsImpl) checkInvariants()
+func (fs *fsImpl) checkInvariants() {
+	// INVARIANT: For each v in inodes, v.lookupCount >= 0
+	for _, v := range fs.inodes {
+		if !(v.lookupCount >= 0) {
+			panic("Negative lookup count")
+		}
+	}
+
+	// INVARIANT: For each k in inodes, k < nextInodeID
+	for k, _ := range fs.inodes {
+		if !(k < fs.nextInodeID) {
+			panic("Unexpectedly large inode ID")
+		}
+	}
+}
 
 func (fs *fsImpl) Init(
 	op *fuseops.InitOp) {